Synthetic resin emulsion powder

ABSTRACT

Disclosed is a synthetic resin emulsion powder obtained by spray-drying a composition that comprises an emulsion (A) where the dispersoid is a polymer that having one or more unsaturated monomer units selected from ethylenic unsaturated monomers and dienic monomers, and a polyvinyl alcohol (B) having, in the molecule, from 1 to 12 mol % of ethylene units. The emulsion powder has good redispersibility and good water resistance. Its redispersion well form good films and has good storage stability at low temperatures. The emulsion powder is favorable for additives to hydraulic substances, as it well disperses in hydraulic substances such as cement mortar and gives hardened articles of high mechanical strength. The emulsion powder is also favorable for joint materials for hydraulic substances, as its adhesiveness and durability are both good and gives jointed articles of high mechanical strength.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to synthetic resin emulsion powder. Moreprecisely, the invention relates to synthetic resin emulsion powderobtained by spray-drying a composition that comprises an emulsion (A)where the dispersoid is a polymer having one or more unsaturated monomerunits selected from ethylenic unsaturated monomers and dienic monomers,and a polyvinyl alcohol (B) having an ethylene unit content of from 1 to12 mol %.

2. Description of the Related Art

Synthetic resin emulsion powder is produced by spray-drying a syntheticresin emulsion, and is superior to the starting emulsion thereof inpoint of the processability and the transportability as it is powdery.Before use, water may be added to the powder and stirred, whereby thepowder may readily redisperse in water. Accordingly, the powder is muchused in various applications for additives to cement and mortar,adhesives, binders for coating compositions, etc. In particular, sincethe powder can be premixed with mortar to realize various modificationsof commercial products, and it is especially favorable for additives tomortar and is therefore widely used in the art. However, whenconventional synthetic resin emulsions are directly spray-dried, thenthe dispersoid particles therein may readily fuse together and could notredisperse in water. At present, therefore, a large amount of polyvinylalcohol must be added later to the emulsions, or a large amount ofinorganic powder such as silicic anhydride that serves as anantiblocking agent must be in the emulsions to solve the problem. Forthe polyvinyl alcohol that is added later to the emulsions, partiallysaponified (hydrolyzed) PVA has heretofore been widely used (see JP-A11-263849, claim 1 and paragraphs [0011] and [0012]) since it must bepowdered and must be re-emulsified before use. However, as will beobvious from Comparative Examples 7 and 8 given hereinunder, theredispersibility of the PVA powder is not always good, and, in addition,another problem with the PVA powder is that the water resistance of theemulsion obtained through redispersion of the emulsion powder isinferior to that of the original emulsion.

Also known is a powder for that purpose, that is obtained byspray-draying an emulsion with a mercapto-terminated polyvinyl alcoholserving as a dispersant (see JP-A 9-151221, claim 1 and paragraphs[001]) and [0020]). Further known is a powder that is obtained byspray-drying an emulsion with a 1,2-glycol bond-rich PVA which isprepared through high-temperature polymerization and serves as adispersant (see JP-A 2001-342260, claim 1). The redispersibility ofthese synthetic resin emulsion powders is good, as is apparent fromComparative Examples 26 to 27 given hereinunder, but is not stillsatisfactory. For example, when the powders are used as additives tocement mortar, the mechanical strength of the resulting cement mortar isnot always satisfactory.

SUMMARY OF THE INVENTION

An object of the invention is to solve the problems as above and toprovide synthetic resin emulsion powder of good redispersibility andwater resistance, of which the redispersion has good film formabilityand storage stability at low temperatures.

Another object of the invention is to provide synthetic resin emulsionpowder which, when used as an additive to hydraulic substances or as ajoint material for them, gives hardened constructions of high strength.

The above-mentioned objects are attained by providing a synthetic resinemulsion powder which is obtained by drying a composition that comprisesan emulsion (A) where the dispersoid is a polymer having one or moreunsaturated monomer units selected from ethylenic unsaturated monomersand dienic monomers, and a polyvinyl alcohol (B) having an ethylene unitcontent of from 1 to 12 mol %.

Preferably, the objects are attained by providing a synthetic resinemulsion powder obtained by drying a composition that comprises anemulsion (A) where the dispersant is a polyvinyl alcohol and thedispersoid is a polymer having one or more unsaturated monomer unitsselected from ethylenic unsaturated monomers and dienic monomers, and apolyvinyl alcohol (B) having an ethylene unit content of from 1 to 12mol % added thereto.

Also preferably, the objects are attained by providing a synthetic resinemulsion powder which is obtained by spray-drying an emulsion (A) wherethe dispersant is a polyvinyl alcohol (B) having an ethylene unitcontent of from 1 to 12 mol % and the dispersoid is a polymer having oneor more unsaturated monomer units selected from ethylenic unsaturatedmonomers and dienic monomers.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The synthetic resin emulsion powder of the invention is described indetail hereinunder.

In the invention, the dispersoid of the emulsion (A) comprises a polymerhaving one or more unsaturated monomer units selected from ethylenicunsaturated monomers and dienic monomers. The ethylenic unsaturatedmonomers include, for example, olefins such as ethylene, propylene,isobutene; halogeno-olefins such as vinyl chloride, vinylidene chloride,vinyl fluoride, vinylidene fluoride; vinyl esters such as vinyl formate,vinyl acetate, vinyl propionate, vinyl versatate, vinyl pivalate;acrylic acid and acrylates such as methyl acrylate, ethyl acrylate,n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butylacrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate,octadecyl acrylate; methacrylic acid and methacrylates such as methylmethacrylate, ethyl methacrylate, n-propyl methacrylate, i-propylmethacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butylmethacrylate, 2-ethylhexylmethacrylate, dodecyl methacrylate, octadecylmethacrylate; nitriles such as acrylonitrile, methacrylonitrile; allylcompounds such as allyl acetate, allyl chloride; styrene monomers suchas styrene, α-methylstyrene, p-methylstyrenesulfonic acid and its sodiumand potassium salts; trimethyl(3-acrylamido-3-dimethylpropyl)ammoniumchloride, 3-acrylamidopropyltrimethylammonium chloride,3-methacrylamidopropyltrimethylammonium chloride,N-(3-allyloxy-2-hydroxypropyl)dimethylamine quaternary ammonium salt,N-(4-allyloxy-3-hydroxybutyl)diethylamine quaternary ammonium salt, aswell as quaternary ammonium salts of acrylamide, N-methylacrylamide,N-ethylacrylamide, N,N-dimethylacrylamide, diacetonacrylamide,N-methylolacrylamide, methacrylamide, N-methylmethacrylamide,N-ethylmethacrylamide, N-methylolmethacrylamide; andhydroxypropyltrimethylammonium chloride methacrylate,hydroxypropyltrimethylammonium chloride acrylate, N-vinylpyrrolidone.The dienic monomers include, for example, butadiene, isoprene,chloroprene. One or more of these monomers may be used herein eithersingly or as combined.

Of the polymers that comprise any of the above-mentioned monomer units,preferred for use in the invention are polyvinyl esters such astypically polyvinyl acetate, and olefin-vinyl ester copolymers such astypically ethylene-vinyl acetate copolymer.

The polyvinyl alcohol (B) having an ethylene unit content of from 1 to12 mol % for use in the invention may be obtained through saponificationof a copolymer of a vinyl ester and ethylene. It is a matter ofimportance that the ethylene unit content of the polyvinyl alcohol (B)is from 1 to 12 mol % in one molecule. Preferably, the ethylene unitcontent is at least 1.5 mol %, more preferably at least 2 mol %. If theethylene unit content is lower than the range, the redispersibility ofthe emulsion powder is not good, as is obvious from Comparative Example5 given hereinunder; but if higher than the range, the redispersibilityof the emulsion powder is extremely bad and the film formability thereofis also bad, as is obvious from Comparative Example 6 and ComparativeExample 9 given hereinunder.

One preferred embodiment of the polyvinyl alcohol (B) that has anethylene unit content of from 1 to 12 mol % for use in the invention hasa 1,2-glycol bond content of from (1.7-X/40) to 4 mol % in which X (mol%) indicates the ethylene unit content of the polymer. Using the polymerof the preferred type further improves the redispersibility of theemulsion powder obtained herein.

For producing the polymer of the type, for example, employable is amethod of copolymerizing vinylene carbonate with a vinyl ester monomerand ethylene in such a controlled manner that the 1,2-glycol bondcontent of the resulting copolymer could fall within the range as above;or a method of copolymerizing ethylene and a vinyl ester monomer underpressure in such a controlled manner that the polymerization temperatureis kept higher than usual, for example, falling between 75 and 200° C.Though not specifically defined, the polymerization temperature in thelatter method preferably falls between 95 and 190° C., more preferablybetween 100 and 160° C.

In this case, the 1,2-glycol bond content is preferably at least(1.7-X/40) mol %, more preferably at least (1.75-X/40), most preferablyat least (1.8-X/40). Also preferably, the 1,2-glycol bond content is atmost 4 mol %, more preferably at most 3.5 mol %, most preferably at most3.2 mol %. The 1,2-glycol bond content of the polymer may be obtainedthrough NMR spectral analysis thereof.

Not interfering with the advantages of the invention, the polyvinylalcohol (B) may be a copolymer with any copolymerizable ethylenicunsaturated monomer. The ethylenic unsaturated comonomer includes, forexample, acrylic acid, methacrylic acid, fumaric acid, maleic acid(anhydride), itaconic acid, acrylonitrile, methacrylonitrile,acrylamide, methacrylamide,trimethyl-(3-acrylamido-3-dimethylpropyl)-ammonium chloride,acrylamido-2-methylpropanesulfonic acid and its sodium salt, ethyl vinylether, butyl vinyl ether, vinyl chloride, vinyl bromide, vinyl fluoride,vinylidene chloride, vinylidene fluoride, tetrafluoroethylene, sodiumvinylsulfonate, sodium allylsulfonate, N-vinylpyrrolidone, as well asN-vinylamides such as N-vinylformamide, N-vinylacetamide. Though notspecifically defined, the amount of the copolymerizable monomer may begenerally at most 5 mol %. Also usable herein are terminal-modifiedcopolymers that are produced by copolymerizing a vinyl ester monomersuch as vinyl acetate with ethylene in the presence of a thiol compoundsuch as thiolacetic acid or mercaptopropionic acid, followed byhydrolyzing the resulting copolymer.

The amount of the polyvinyl alcohol (B) to be in the composition ispreferably at least 1 parts by weight and also at most 50 parts byweight, relative to 100 parts by weight of the solid content(dispersoid) of the synthetic resin emulsion (A) therein. If the amountof the polyvinyl alcohol (B) is smaller than 1 part by weight, theredispersibility of the powdered emulsion may be poor, and, in addition,the mechanical stability of the emulsion powder added to a hydraulicsubstance may be poor and the dispersibility of the emulsion powder in ahydraulic substance may also be poor. If, however, the amount is largerthan 50 parts by weight, then the physical properties such as the waterresistance of the emulsion powder obtained may be poor and, in addition,the strength of the hydraulic substance that contains the emulsionpowder may lower.

Next described is an embodiment of the invention, a synthetic resinemulsion that is obtained by adding a polyvinyl alcohol (B) having from1 to 12 mol % of ethylene units in the molecule to an emulsion (A) ofwhich the dispersoid is a polymer having one or more unsaturated monomerunits selected from ethylenic unsaturated monomers and dienic monomers.

The dispersant for the emulsion (A) is preferably a polyvinyl alcohol.The polyvinyl alcohol is, for example, any of an ordinary polyvinylalcohol that is produced through saponification of a polyvinyl esterobtained by polymerizing a vinyl ester; a polyvinyl alcohol having a1,2-glycol bond content of at least 1.9 mol % that will be describedhereinunder; or the above-mentioned polyvinyl alcohol (B). Of those,preferred is a polyvinyl alcohol having a 1,2-glycol bond content of atleast 1.9 mol % as it betters the redispersibility of the syntheticresin powder containing it and improves the water resistance and themechanical strength of the hydraulic substance containing it.

Though not specifically defined, the saponification degree of thepolyvinyl alcohol to be used herein for the dispersant in the emulsion(A) is preferably from 70 to 99 mol %, more preferably from 80 to 98 mol%, even more preferably from 83 to 95 mol %. If the saponificationdegree thereof is lower than 70 mol %, the solubility in water of thepolyvinyl alcohol that is intrinsic thereto may lower. If, however, thesaponification degree thereof is higher than 99 mol %, the emulsionpolymerization to give the polymer may be unstable. Also though notspecifically defined, the viscosity-average degree of polymerization(hereinafter this will be abbreviated as the degree of polymerization)of the polyvinyl alcohol is preferably from 100 to 8000, more preferablyfrom 300 to 3000, most preferably from 300 to 2500.

Not detracting from the advantages of the invention, the polyvinylalcohol may be copolymerized with any other ethylenic unsaturatedmonomer, for example, as in the above-mentioned polyvinyl alcohol (B).

The synthetic resin emulsion (A) for use in the invention may beobtained through emulsion polymerization of one or more monomersselected from ethylenic unsaturated monomers and dienic monomers in thepresence of the above-mentioned polyvinyl alcohol. In producing thesynthetic resin emulsion, the initiator for the emulsion polymerizationmay be any ordinary polymerization initiator generally used in ordinaryemulsion polymerization, for example, water-soluble initiators such aspotassium persulfate, ammonium persulfate, hydrogen peroxide, t-butylhydroperoxide; oil-soluble initiators such as azobisisobutyronitrile,benzoyl peroxide. These may be used either singly or as a redox systemcombined with some reducing agent. The method of using it is notspecifically defined. For example, it may be added to the polymerizationsystem all at a time in the initial stage, or may be continuously addedthereto.

In the synthetic resin emulsion (A) for use in the invention, the amountof the polyvinyl alcohol is not specifically defined. In general, it maybe from 2 to 30 parts by weight, preferably from 3 to 15 parts byweight, more preferably 3 to 10 parts, relative to 100 parts by weightof the dispersoid, that is, the monomer to be polymerized in thepresence of it.

The mode of adding the polyvinyl alcohol to the system is not alsospecifically defined. It may be added thereto all at a time in theinitial stage, or a part of it is added thereto in the initial stage andthe remaining part thereof may be continuously added thereto during thepolymerization.

Regarding the addition of the monomer in producing the synthetic resinemulsion (A) for use in the invention, employable are various methods.For example, the monomer may be added to the polymerization system allat a time in the initial stage; or a part of the monomer may be addedthereto in the initial stage and the remaining part thereof may becontinuously added thereto during the polymerization; or the monomer ispreviously emulsified with water along with a dispersant and theresulting emulsion may be continuously added to the polymerizationsystem.

If desired, a chain transfer agent may be added to the system inproducing the synthetic resin emulsion (A) for use in the invention. Notspecifically defined, the chain transfer agent may be any and every onethat causes chain transfer in polymer. In view of the efficiency inchain transfer with it, preferred for use herein are mercaptogroup-having compounds. The mercapto group-having compounds are, forexample, alkylmercaptans such as n-octylmercaptan, n-dodecylmercaptan,t-dodecylmercaptan; and 2-mercaptoethanol, 3-mercaptopropionic acid.

The amount of the chain transfer agent to be added to the system ispreferably at most 5 parts by weight relative to 100 parts by weight ofthe monomer. If the amount of the chain transfer agent added is over 5parts by weight, the polymerization stability of the synthetic resinemulsion produced will be poor and, in addition, the molecular weight ofthe polymer to form the dispersoid may greatly lower and, as a result,the physical properties of the emulsion may be thereby worsened.

Thus obtained, the polyvinyl alcohol (B) is added to the emulsion (A) toobtain the synthetic resin emulsion for use in the invention.

For adding the polyvinyl alcohol (B) to the emulsion (A), for example,one preferred method comprises adding an aqueous solution of polyvinylalcohol (B) to emulsion (A). Apart from it, also employable is a methodof adding a powder, flakes or pellets of the polyvinyl alcohol (B) tothe emulsion (A). Still another method employable for it comprisesadding the polyvinyl alcohol (B) to the emulsion (A) being preparedthrough emulsion polymerization, all at a time or continuously, in thelatter stage of emulsion polymerization to give the emulsion (A).

The degree of polymerization of the polyvinyl alcohol (B) to be added tothe emulsion (A) may be determined in consideration of variousconditions, not specifically defined. For easy operation to powder theemulsion, in general, it may be preferably from 100 to 3000, morepreferably from 150 to 2000, even more preferably from 200 to 1600, mostpreferably from 200 to 1000. On the other hand, the saponificationdegree of the polyvinyl alcohol (B) is not also specifically defined,but is preferably from 70 to 99 mol %, more preferably from 75 to 98 mol%, even more preferably from 80 to 96 mol %.

The amount of the polyvinyl alcohol (B) to be added to 100 parts byweight of the solid content of the emulsion (A) is preferably from 1 to50 parts by weight, more preferably from 3 to 30 parts by weight, evenmore preferably from 5 to 30 parts by weight, most preferably from 7 to20 parts by weight.

Next described is another embodiment of the invention for obtaining anemulsion (A) in which the dispersant is a polyvinyl alcohol (B) havingan ethylene unit content of from 1 to 12 mol % and the dispersoid is apolymer that contains one or more unsaturated monomer units selectedfrom ethylenic unsaturated monomers and dienic monomers.

In this embodiment, the emulsion (A) may be obtained through emulsionpolymerization of one or more monomers selected from ethylenicunsaturated monomers and dienic monomers, in the presence of a polyvinylalcohol (B) having an ethylene unit content of from 1 to 12 mol % in themolecule, and the condition for producing it may be the same as that forthe above-mentioned emulsion (A).

The amount of the dispersant, polyvinyl alcohol (B) may be preferablyfrom 2 to 30 parts by weight, more preferably from 3 to 15 parts byweight, most preferably from 3 to 10 parts by weight, relative to 100parts by weight of the dispersoid.

The viscosity-average degree of polymerization (hereinafter this will beabbreviated as the degree of polymerization) of the polyvinyl alcohol(B) for the dispersant may be determined in consideration of variousconditions and is not specifically defined. However, in view of theworkability thereof in powdering the emulsion, the degree ofpolymerization of the polyvinyl alcohol (B) is preferably from 100 to8000, more preferably from 300 to 3000, most preferably from 300 to2500. On the other hand, the saponification degree of the polyvinylalcohol (B) is not also specifically defined, but is preferably from 70to 99 mol %, more preferably from 80 to 98 mol %, even more preferablyfrom 83 to 95 mol %.

The mode of adding the dispersant, polyvinyl alcohol (B) to the systemis not specifically defined. For example, it may be added thereto all ata time in the initial stage of polymerization; or a part of thepolyvinyl alcohol (B) may be added to the system in the initial stage ofpolymerization and the remaining part thereof may be continuously addedthereto during the polymerization.

If desired, any known nonionic, anionic, cationic or ampholyticsurfactant or water-soluble polymer such as hydroxyethyl cellulose maybe used along with the polyvinyl alcohol.

Adding a polyvinyl alcohol (C) to the thus-obtained emulsion (A) withthe polyvinyl alcohol (B) serving as the dispersant therein is onepreferred embodiment of the invention. The polyvinyl alcohol (C)includes, for example, ordinary polyvinyl alcohol such as that mentionedhereinabove, the polyvinyl alcohol having a 1,2-glycol bond content ofat least 1.9 mol % to be mentioned hereinunder, and the above-mentionedpolyvinyl alcohol (B).

The degree of polymerization of the polyvinyl alcohol (C) may bedetermined in accordance with various conditions and is not specificallydefined. However, in view of the workability thereof in powdering theemulsion, the degree of polymerization of the polyvinyl alcohol (C) ispreferably from 100 to 3000, more preferably from 150 to 2000, even morepreferably from 200 to 1600, most preferably from 200 to 1000. On theother hand, the saponification degree of the polyvinyl alcohol (C) isnot also specifically defined, but is preferably from 70 to 99 mol %,more preferably from 75 to 98 mol %, even more preferably from 80 to 96mol %.

The amount of the polyvinyl alcohol (C) to be added to the emulsion (A)may be from 1 to 50 parts by weight, preferably from 3 to 30 parts byweight, even more preferably from 5 to 20 parts by weight, mostpreferably from 7 to 20 parts by weight, relative to 100 parts by weightof the solid content dispersoid) of the emulsion (A).

Using a synthetic resin emulsion that is prepared by adding a polyvinylalcohol (D) having a 1,2-glycol bond content of at least 1.9 mol % tothe emulsion (A) in which the dispersant is a polyvinyl alcohol and thedispersoid is a polymer having one or more unsaturated monomer unitsselected from ethylenic unsaturated monomers and dienic monomers is alsoa preferred embodiment of the invention.

This embodiment is described below.

In this, the emulsion (A) may be the same as that mentioned hereinabove.

It is a matter of importance that the 1,2-glycol bond content of thepolyvinyl alcohol (D) to be added to the emulsion (A) is at least 1.9mol %, more preferably at least 1.95 mol %, even more preferably atleast 2.0 mol %, most preferably at least 2.1 mol %. Adding thepolyvinyl alcohol (D) of the type to the emulsion (A) improves theredispersibility of the emulsion powder and, in addition, when theemulsion powder is used for additives or construction joints forhydraulic substances such as cement or cement mortar, it improves thephysical properties such as the bending strength of the hydraulicsubstances. Preferably, the 1,2-glycol bond content of the polyvinylalcohol (D) is at most 4 mol %, more preferably at most 3.5 mol %, mostpreferably at most 3.2 mol %. The 1,2-glycol bond content of the polymermay be obtained through NMR spectral analysis of the polymer.

The method of producing the polyvinyl alcohol (D) having a 1,2-glycolbond content of at least 1.9 mol % is not specifically defined, and maybe any known one. For producing the polymer of the type, for example,employable is a method of copolymerizing vinylene carbonate with a vinylester monomer in such a controlled manner that the 1,2-glycol bondcontent of the resulting copolymer could fall within the range as above;or a method of polymerizing a vinyl ester under pressure in such acontrolled manner that the polymerization temperature is kept higherthan usual, for example, falling between 75 and 200° C. Thepolymerization temperature in the latter method preferably falls between95 and 190° C., more preferably between 100 and 180° C. It is importantthat the condition for pressure is so selected that the polymerizationsystem could be kept at a temperature not higher than the boiling pointthereof. Preferably, the pressure may be at least 0.2 MPa, morepreferably at least 0.3 MPa. The uppermost limit of the pressure ispreferably at most 5 MPa, more preferably at most 3 MPa. Thepolymerization may be effected in any mode of bulk polymerization,solution polymerization, suspension polymerization, emulsionpolymerization or the like, in the presence of a radical polymerizationinitiator. In particular, preferred is solution polymerizationespecially in a solvent of methanol. Thus prepared, the polyvinyl estermay be subjected to saponification in any ordinary manner to give thepolyvinyl alcohol for use herein.

The degree of polymerization of the polyvinyl alcohol (D) may bedetermined in accordance with various conditions and is not specificallydefined. However, in view of the workability thereof in powdering theemulsion, in general the degree of polymerization of the polyvinylalcohol (D) is preferably from 100 to 3000, more preferably from 150 to2000, even more preferably from 200 to 1600, most preferably from 200 to1000. On the other hand, the saponification degree of the polyvinylalcohol (D) is not also specifically defined, but is preferably from 70to 99 mol %, more preferably from 75 to 98 mol %, even more preferablyfrom 80 to 96 mol %.

Not detracting from the advantages of the invention, the polyvinylalcohol (D) may be copolymerized with any ethylenic unsaturated monomersuch as that as in the above-mentioned polyvinyl alcohol (B).

The amount of the polyvinyl alcohol (D) to be added to the syntheticresin emulsion (A) may be preferably from 1 to 50 parts by weight, morepreferably from 3 to 30 parts by weight, even more preferably from 5 to20 parts by weight, most preferably from 7 to 20 parts by weight,relative to 100 parts by weight of the solid content (dispersoid) of theemulsion (A). Adding the polyvinyl alcohol (D) of the type to theemulsion (A) improves the redispersibility of the emulsion powder thatis obtained after drying the emulsion, and, in addition, it alsoimproves the dispersibility of the emulsion powder in hydraulicsubstances whereby the strength of the hydraulic substances with theemulsion powder therein may be thereby increased.

The synthetic resin emulsion powder of the invention may be obtained bydrying the synthetic resin emulsion that has been obtained according tothe method mentioned hereinabove, preferably by spray-drying it.Spray-drying the emulsion may be effected in any ordinary manner ofspraying and drying a liquid. Regarding the spraying mode for it, theemulsion may be sprayed with any of discs, nozzles or shock waves. Forthe heat source, employable is any of hot air or hot steam. The dryingcondition may be suitably determined depending on the size and the typeof the spraying drier used, and on the concentration, the viscosity andthe flow rate of the synthetic resin emulsion to be spray-dried. Thedrying temperature range suitably falls between 100° C. and 150° C.,within which it is desirable that the other drying conditions aredetermined so as to obtain well dried powder.

For improving the storage stability and the redispersibility in water ofthe synthetic resin emulsion powder of the invention, it is desirable toadd inorganic powder (antiblocking agent) to the emulsion powder. Theinorganic powder may be added to the spray-dried emulsion powder anduniformly mixed with it. However, it is desirable that the syntheticresin emulsion is sprayed in the presence of an inorganic powder(simultaneous spraying of emulsion along with inorganic powder) for moreuniformly mixing them. Preferably, the inorganic powder is a particlepowder having a mean particle size of from 0.1 to 100 μm. For theinorganic powder, preferred is a powder of fine particles, for which,for example, usable are calcium carbonate, clay, silicic anhydride,aluminium silicate, white carbon, talc, and alumina white. Of thoseinorganic powders, more preferred is silicic anhydride. The amount ofthe inorganic powder is preferably at most 20% by weight, morepreferably at most 10% by weight, in view of its properties. Thelowermost limit of the amount is preferably at least 0.1% by weight,more preferably at least 0.2% by weight. Organic fillers may also beused for the powder.

For further improving the redispersibility in water of the syntheticresin emulsion powder, various water-soluble additives may be added tothe powder. Preferably, the additive is added to the synthetic resinemulsion before the emulsion is spray-dried, as it may be uniformlymixed with the resulting emulsion powder. The amount of thewater-soluble additive to be added is not specifically defined and maybe suitably so controlled that it does not have any negative influenceon the physical properties such as water resistance of the emulsion. Theadditives include, for example, hydroxyethyl cellulose, methylcellulose, starch derivatives, polyvinylpyrrolidone, polyethylene oxide,as well as water-soluble alkyd resins, water-soluble phenolic resins,water-soluble urea resins, water-soluble melamine resins, water-solublenaphthalenesulfonic acid resins, water-soluble amino resins,water-soluble polyamide resins, water-soluble acrylic resins,water-soluble polycarboxylic acid resins, water-soluble polyesterresins, water-soluble polyurethane resins, water-soluble polyol resins,water-soluble epoxy resins.

The synthetic resin emulsion powder of the invention (having a meanparticle size of from 1 to 1000 Mm, preferably from 2 to 500 μm) may bedirectly used for various application as it is, but if desired, it maybe combined with any other conventional known emulsion or emulsionpowder not detracting from the advantages of the invention.

The synthetic resin emulsion powder of the invention is especiallyuseful for additives to hydraulic substances or for joint materials forhydraulic substances. The hydraulic substances as referred to hereininclude, for example, hydraulic cement such as Portland cement, aluminacement, slag cement, fly ash cement; and other hydraulic materials thancement, such as gypsum and plaster.

In case where the additive to such hydraulic substances is added, forexample, to cement mortar that comprises cement, aggregate and water,its amount is preferably from 5 to 20% by weight of cement. Theaggregate may be any of fine aggregate such as river sand, ground sand,color sand and siliceous sand; and coarse aggregate such as river graveland ground stones.

In case where the synthetic resin emulsion powder of the invention isused for a joint material for hydraulic substances, the powder issuitably re-emulsified in water and applied onto a hydraulic substancesubstrate of concrete or the like to be a joint material(primer-processing agent) for it, and then a hydraulic substance such ascement mortar is stuck onto it. Using the joint material of the typeensures good adhesiveness and good durability and even good mechanicalstrength of the bonded articles.

For further improving the dispersibility of the synthetic resin emulsionpowder of the invention that serves as additives or joint materials forhydraulic substances, various additives may be added to the emulsionpowder. Preferably, the additives are added to the synthetic resinemulsion before the emulsion is spray-dried, and then the resultingmixture is spray-dried, as the process gives uniform mixtures.Preferably, the additives are soluble in water. Not specificallydefined, the amount of the water-soluble additive to be in the resinemulsion powder may be suitably so controlled that it does not have anynegative influence on the physical properties such as water resistanceof the emulsion. The additives include, for example, hydroxyethylcellulose, methyl cellulose, starch derivatives, polyvinylpyrrolidone,polyethylene oxide, as well as water-soluble alkyd resins, water-solublephenolic resins, water-soluble urea resins, water-soluble melamineresins, water-soluble naphthalenesulfonic acid resins, water-solubleamino resins, water-soluble polyamide resins, water-soluble acrylicresins, water-soluble polycarboxylic acid resins, water-solublepolyester resins, water-soluble polyurethane resins, water-solublepolyol resins, water-soluble epoxy resins.

In case where the synthetic resin emulsion powder of the invention isused for additives or joint materials for hydraulic substances,especially for additives to cement and mortar, any of AE agent(Air-Entraining Admixtures), water-reducing agent, fluidizing agent,water-retaining agent, thickener, waterproofing agent, defoaming agentand the like may be suitably added thereto.

The synthetic resin emulsion powder of the invention may also be usedfor adhesives, coating compositions, paper processing agents and others.For those applications, the emulsion powder may suitably contain any ofviscosity improver, water-retaining agent, tackifier, thickener, pigmentdispersant, stabilizer, etc.

EXAMPLES

The invention is described concretely with reference to the followingExamples, which, however, are not intended to restrict the scope of theinvention. In the Examples, “part” and “%” are all by weight.

Emulsion Production Example 1

80 parts of aqueous 9.5% solution of “PVA217” (by Kuraray, having adegree of polymerization of 1700 and a saponification degree of 88 mol%) was fed into a pressure autoclave equipped with a nitrogen inletmouth, a thermometer and a stirrer, heated up to 60° C., and then purgedwith nitrogen. 80 parts of vinyl acetate was fed into it, and thenethylene was into it to an increased pressure of 4.9 MPa. 2 g of aqueous0.5% hydrogen peroxide solution and 0.3 g of aqueous 2% Rongalitesolution were fed into it under pressure, and the polymerization wasthen started. When the remaining vinyl acetate concentration reached10%, ethylene was discharged out until the ethylene pressure was loweredto 2.0 MPa. Then, 0.3 g of aqueous 3% hydrogen peroxide solution wasintroduced into it under pressure to complete the polymerization. Duringthe polymerization, no aggregation was found, and the polymerizationstability of the system was good. The process gave ethylene-vinylacetate copolymer emulsion (Em-1) having a solid concentration of 55%and an ethylene content of 18% by weight.

Emulsion Production Example 2

5 parts of mercapto-terminated PVA (having a degree of polymerization of550, a saponification degree of 88.3 mol % and a mercapto group contentof 3.3×10⁻⁵ equivalent/g) and 90 parts of ion-exchanged water were fedinto a glass vessel equipped with a reflux condenser, a dropping funnel,a thermometer, a nitrogen inlet mouth and a stirrer, and completelydissolved at 95° C. Next, its pH was made to be 4 with diluted sulfuricacid added thereto, and then 10 parts of methyl methacrylate, 10 partsof n-butyl acrylate and 0.1 parts of n-dodecylmercaptan were added to itwith stirring at 150 rpm. This was purged with nitrogen and heated up to70° C. 5 parts of 1% potassium persulfate was added to it to start thepolymerization. Then, a mixture of 40 parts of methyl methacrylate, 40parts of n-butyl acrylate and 0.4 parts of n-dodecylmercaptan wascontinuously added to it, over a period of 2 hours. 3 hours after thestart of the polymerization, the conversion reached 99.5%, and thepolymerization was stopped in this stage. The process gave stable methylmethacrylate/n-butyl acrylate copolymer emulsion (Em-2) having a solidconcentration of 52.0%.

Emulsion Production Example 3

An emulsion (Em-3) was produced in the same manner as in EmulsionProduction Example 2, for which, however, a mercapto-terminated PVA(having an ethylene content of 0.5 mol %, a degree of polymerization of550, a saponification degree of 88.3%, and a mercapto group content of3.3×10⁻⁵ equivalent/g) was used in place of the mercapto-terminated PVA(having a degree of polymerization of 550, a saponification degree of88.3 mol %, and a mercapto group content of 3.3×10— equivalent/g) inEmulsion Production Example 2.

Example 1

A mixture of 100 parts, in terms of the solid content thereof, of theethylene-vinyl acetate copolymer emulsion (A) (Em-1) obtained inEmulsion Production Example 1 and 200 parts of aqueous 5% solution ofethylene-modified PVA (B) (PVA-1 having an ethylene unit content of 5 ml%, a degree of polymerization of 500 and a saponification degree of 95mol %), and 2%, relative to the solid content of the emulsion, of finepowder of silicic anhydride (having a mean particle size of 2 μm) wereseparately sprayed into hot air at 120° C. at the same time and dried toobtain an emulsion powder having a mean particle size of 20 μm.

Property Evaluation of Emulsion Powder:

100 parts of ion-exchanged water at 20° C. was added to 100 parts of theemulsion powder and well stirred in a stirrer, and this evaluated forthe following physical properties thereof.

The results are given in Table 1.

Redispersibility:

The redispersed emulsion was filtered through a 200-mesh stainless metalgauze filter, the residue was dried at 105° C. for 5 hours, and itsratio was measured.

Filtration Residue (%)=(weight of dried residue/weight of redispersedemulsion powder)×100.

The smaller filtration residue means that the emulsion powder giveshardened articles having a better mechanical strength when it is usedfor additives or joint materials for hydraulic substances.

The invention gives emulsion powder having a filtration residue of notlarger than 5% (see Table 1), and even emulsion powder having afiltration residue of not larger than 3% (see Table 2-1), and still evenemulsion powder having a filtration residue of not larger than 2%, oreven not larger than 1% (see Table 3-1).

Condition after Redispersion:

The condition of the redispersed emulsion was observed with the nakedeye and with an optical microscope, and evaluated according to thefollowing criteria:

⊚: Excellent; The redispersion was uniform and had a mean particle sizeof not larger than 50 μm.

◯: Good; The redispersion was uniform and contained no non-dispersedmatter (blobs).

Δ: Fair; Though redispersed, the emulsion still contained non-dispersedmatter.

x: Poor; Not redispersed.

Film Formability:

The redispersion was cast on a glass plate at 50° C. and dried, and itsfilm formability was evaluated according to the following criteria:

◯: Excellent; A uniform film was formed, and it was tough.

Δ: Fair; A film was formed, but it was brittle.

x: Poor; No uniform film was formed.

Water Resistance (Film Dissolution in Water):

At 20° C., the redispersed emulsion was formed into a film having athickness of 100 μm. The film was dipped in water at 20° C. for 24hours, and its dissolution was calculated according to the followingequation:

Dissolution (%)={1−(absolute dry weight of dipped film)/(absolute dryweight of non-dipped film))×100,

wherein the absolute dry weight of the non-dipped film is representedby:

wet weight of non-dipped film−(wet weight of non-dipped film×watercontent (%) of film/100);

the absolute dry weight of the dipped film means the weight of thedipped film absolutely dried at 105° C.

The smaller dissolution means that the emulsion powder has better waterresistance and better redispersibility. The invention gives emulsionpowder of which the film dissolution is not higher than 10% (see Table3-1), preferably not higher than 8% (see Table 2-1), more preferably ornot higher than 7% (see Table 1).

Storage Stability:

The redispersed emulsion was left at 20° C. and at 0° C. After 1 week,its condition was observed and evaluated according to the followingcriteria:

◯: Excellent; No change.

Δ: Fair; Thickened.

x: Poor; Gelled.

Gel Content:

The emulsion powder was redispersed in water at 20° C. Concretely, 100parts of the emulsion powder was redispersed in 100 parts ofion-exchanged water at 20° C. The resulting redispersion was cast onto aPET (polyethylene terephthalate film at 20° C. and 65% RH, and dried for7 days to form a dry film thereon having a thickness of 500 μm. The filmwas blanked out to give a circular piece having a diameter of 2.5 cm.Thus prepared, the sample was subjected to Soxhlet extraction withacetone for 24 hours, and then further extracted in boiling water for 24hours. After thus extracted, the insoluble fraction (gel content) of thefilm was obtained.

Gel Content (%)=(absolute dry weight of extracted film)/(absolute dryweight of non-extracted film)×100,

wherein the absolute dry weight of the non-extracted film is representedby:

wet weight of non-extracted film−(wet weight of non-extracted film×watercontent (%) of film/100);

the water content of film is obtained by absolutely drying a sample ofthe film (this differs from the sample of the film to be extracted withacetone and boiling water) at 105° C. for 4 hours, followed by measuringin advance the water content of the film sample;the absolute dry weight of the extracted film means the weight of theextracted film absolutely dried at 105° C. for 4 hours.

The larger gel content means that the polyvinyl alcohol (B) is graftedto a higher degree on the dispersoid (polymer) and the redispersibilityof the emulsion powder is thereby improved better. The invention givesemulsion powder of which the gel content is not lower than 20% (seeTable 1, Table 3-1), preferably not lower than 30% (see Table 2-1).

Example 2

An emulsion powder was produced in the same manner as in Example 1, forwhich, however, an ethylene-modified PVA (B) (PVA-2 having an ethyleneunit content of 10 mol %, a degree of polymerization of 500 and asaponification degree of 98 mol %) was used in place of theethylene-modified PVA (B) (PVA-1) in Example 1. Also in the same manneras in Example 1, the physical properties of the emulsion powder thusobtained herein were measured and evaluated. The results are given inTable 1.

Example 3

An emulsion powder was produced in the same manner as in Example 1, forwhich, however, an ethylene-modified PVA (B) (PVA-3 having an ethyleneunit content of 5 mol % % a degree of polymerization of 500 and asaponification degree of 88 mol %) was used in place of theethylene-modified PVA (B) (PVA-1) in Example 1. Also in the same manneras in Example 1, the physical properties of the emulsion powder thusobtained herein were measured and evaluated. The results are given inTable 1.

Comparative Example 1

An emulsion powder was obtained in the same manner as in Example 1, forwhich, however, a non-modified PVA (B) (PVA-4, Kuraray's “PVA105” havinga degree of polymerization of 500 and a saponification degree of 98.5mol %) was used in place of the ethylene-modified PVA (B) (PVA-1) inExample 1. Also in the same manner as in Example 1, the physicalproperties of the emulsion powder thus obtained herein were measured andevaluated. The results are given in Table 1.

Comparative Example 2

An emulsion powder was obtained in the same manner as in Example 1, forwhich, however, a non-modified PVA (B) (PVA-5, Kuraray's “PVA205” havinga degree of polymerization of 500 and a saponification degree of 88 mol%) was used in place of the ethylene-modified PVA (B) (PVA-1) inExample 1. Also in the same manner as in Example 1, the physicalproperties of the emulsion powder thus obtained herein were measured andevaluated. The results are given in Table 1.

Comparative Example 3

An emulsion powder was obtained in the same manner as in Example 1, forwhich, however, the ethylene-modified PVA (B) (PVA-1) was not used. Alsoin the same manner as in Example 1, the physical properties of theemulsion powder thus obtained herein were measured and evaluated. Theresults are given in Table 1.

Example 4

An emulsion powder was produced in the same manner as in Example 1, forwhich, however, an ethylene-modified PVA (B) (PVA-6 having an ethyleneunit content of 5 mol %, a degree of polymerization of 1300 and asaponification degree of 93 mol %) was used in place of theethylene-modified PVA (B) (PVA-1) in Example 1. Also in the same manneras in Example 1, the physical properties of the emulsion powder thusobtained herein were measured and evaluated. The results are given inTable 1.

Comparative Example 4

An emulsion powder was obtained in the same manner as in Example 1, forwhich, however, a non-modified PVA (B) (PVA-7, Kuraray's “PVA613” havinga degree of polymerization of 1300 and a saponification degree of 95 mol%) was used in place of the ethylene-modified PVA (B) (PVA-1) inExample 1. Also in the same manner as in Example 1, the physicalproperties of the emulsion powder thus obtained herein were measured andevaluated. The results are given in Table 1.

Example 5

An emulsion powder was produced in the same manner as in Example 1, forwhich, however, used was 100 parts of aqueous 5% solution of theethylene-modified PVA (B) (PVA-1). Also in the same manner as in Example1, the physical properties of the emulsion powder thus obtained hereinwere measured and evaluated. The results are given in Table 1.

Example 6

An emulsion powder was produced in the same manner as in Example 1, forwhich, however, used was 300 parts of aqueous 5% solution of theethylene-modified PVA (B) (PVA-1). Also in the same manner as in Example1, the physical properties of the emulsion powder thus obtained hereinwere measured and evaluated. The results are given in Table 1.

Example 7

An emulsion powder was produced in the same manner as in Example 1, forwhich, however, used was 40 parts of aqueous 5% solution of theethylene-modified PVA (B) (PVA-1). Also in the same manner as in Example1, the physical properties of the emulsion powder thus obtained hereinwere measured and evaluated. The results are given in Table 1.

Example 8

An emulsion powder was produced in the same manner as in Example 1, forwhich, however, used was 500 parts of aqueous 5% solution of theethylene-modified PVA (B) (PVA-1). Also in the same manner as in Example1, the physical properties of the emulsion powder thus obtained hereinwere measured and evaluated. The results are given in Table 1.

Example 9

An emulsion powder was produced in the same manner as in Example 1, forwhich, however, an ethylene-modified PVA (B) (PVA-8 having an ethyleneunit content of 2.5 mol %, a degree of polymerization of 500 and asaponification degree of 88 mol %) was used in place of theethylene-modified PVA (B) (PVA-1) in Example 1. Also in the same manneras in Example 1, the physical properties of the emulsion powder thusobtained herein were measured and evaluated. The results are given inTable 1.

Example 10

An emulsion powder was produced in the same manner as in Example 1, forwhich, however, an ethylene-modified PVA (B) (PVA-9 having an ethyleneunit content of 1.5 mol %, a degree of polymerization of 500 and asaponification degree of 88 mol %) was used in place of theethylene-modified PVA (B) (PVA-1) in Example 1. Also in the same manneras in Example 1, the physical properties of the emulsion powder thusobtained herein were measured and evaluated. The results are given inTable 1.

Comparative Example 5

An emulsion powder was produced in the same manner as in Example 1, forwhich, however, an ethylene-modified PVA (B) (PVA-10 having an ethyleneunit content of 0.5 mol %, a degree of polymerization of 500 and asaponification degree of 95 mol %) was used in place of theethylene-modified PVA (B) (PVA-1) in Example 1. Also in the same manneras in Example 1, the physical properties of the emulsion powder thusobtained herein were measured and evaluated. The results are given inTable 1.

Comparative Example 6

Powdering of emulsion was tried in the same manner as in Example 1, forwhich, however, an ethylene-modified PVA (B) (PVA-11 having an ethyleneunit content of 25 mol %, a degree of polymerization of 500 and asaponification degree of 95 mol %) was used in place of theethylene-modified PVA (B) (PVA-1) in Example 1. However, the PVA becameremarkably cloudy when put into water and could not completely dissolvein water. The cloudy PVA liquid was mixed with the emulsion andprocessed in the same manner as in Example 1. The physical properties ofthe resulting emulsion powder were measured and evaluated also in thesame manner as in Example 1. The results are given in Table 1.

Example 11

An emulsion powder was produced in the same manner as in Example 1, forwhich, however, an ethylene-modified PVA (B) (PVA-12 having an ethyleneunit content of 3 mol %, a 1,2-glycol bond content of 1.9 mol %, adegree of polymerization of 1300 and a saponification degree of 93 mol%) that had been prepared through high-temperature polymerization wasused in place of the ethylene-modified PVA (B) (PVA-1) in Example 1.Also in the same manner as in Example 1, the physical properties of theemulsion powder thus obtained herein were measured and evaluated. Theresults are given in Table 1.

Example 12

An emulsion powder was produced in the same manner as in Example 1, forwhich, however, an ethylene-modified PVA (B) (PVA-13 having an ethyleneunit content of 5 mol %, a 1,2-glycol bond content of 2.2 mol %, adegree of polymerization of 500 and a saponification degree of 88 mol %)that had been prepared through high-temperature polymerization was usedin place of the ethylene-modified PVA (B) (PVA-1) in Example 1. Also inthe same manner as in Example 1, the physical properties of the emulsionpowder thus obtained herein were measured and evaluated.

The results are given in Table 1.

Example 13

An emulsion powder was produced in the same manner as in Example 1, forwhich, however, the methyl methacrylate/n-butyl acrylate copolymeremulsion (A) (Em-2) prepared in Emulsion Production Example 2 was usedin place of Em-1 in Example 1. Also in the same manner as in Example 1,the physical properties of the emulsion powder thus obtained herein weremeasured and evaluated. The results are given in Table 1.

Comparative Example 7

An emulsion powder was produced in the same manner as in Example 13, forwhich, however, non-modified PVA (B) (PVA-5) was used in place of theethylene-modified PVA (B) (PVA-1) in Example 13. In the same manner asin Example 1, the physical properties of the emulsion powder thusobtained herein were measured and evaluated. The results are given inTable 1.

Comparative Example 8

An emulsion powder was produced in the same manner as in ComparativeExample 1, for which, however, Em-3 was used in place of Em-1. In thesame manner as in Example 1, the physical properties of the emulsionpowder thus obtained herein were measured and evaluated. The results aregiven in Table 1.

Comparative Example 9

Powdering of emulsion was tried in the same manner as in Example 1, forwhich, however, an ethylene-modified PVA (B) (PVA-14 having an ethyleneunit content of 15 mol %, a degree of polymerization of 1300 and asaponification degree of 93 mol %) was used in place of theethylene-modified PVA (B) (PVA-1) in Example 1. However, the PVA becamecloudy when put into water and could not completely dissolve in water.The cloudy PVA liquid was mixed with the emulsion and processed in thesame manner as in Example 1. The physical properties of the resultingemulsion powder were measured and evaluated also in the same manner asin Example 1. The results are given in Table 1.

Comparative Example 10

An emulsion powder was produced in the same manner as in Example 1, forwhich, however, a propylene-modified PVA (B) (PVA-15 having a propyleneunit content of 5 mol %, a degree of polymerization of 1300 and asaponification degree of 93 mol %) was used in place of theethylene-modified PVA (B) (PVA-1) in Example 1. Also in the same manneras in Example 1, the physical properties of the emulsion powder thusobtained herein were measured and evaluated. The results are given inTable 1.

Example 14

An ethylene-vinyl acetate copolymer emulsion (Em-4) having a solidconcentration of 55% and an ethylene content of 18% by weight wasprepared in the same manner as in Emulsion Production Example 1, forwhich, however, PVA-31 (having an 1,2-glycol bond content of 2.2 mol %,a degree of polymerization of 1700 and a saponification degree of 88 mol%) that is prepared in PVA Production Example 31 mentioned hereinunderwas used in place of Kuraray's “PVA217” in Emulsion Production Example1.

Next, an emulsion powder was produced in the same manner as in Example1, for which, however, Em-4 was used in place of the ethylene-vinylacetate copolymer emulsion (A) (Em-1) in Example 1. Also in the samemanner as in Example 1, the physical properties of the emulsion powderthus obtained herein were measured and evaluated. The results are givenin Table 1.

The emulsion powders obtained in Examples 1 to 14 and ComparativeExamples 1 to 10 were tried for additives and joint materials forhydraulic substances, and their physical properties were measured andevaluated. The results are given in Table 2.

Property Evaluation of Additives to Hydraulic Substances: Property ofAdditive to Cement Mortar: Physical Test of Cement Mortar:

1) Mortar Composition:

Ratio by weight, additive to hydraulic substance/cement=0.10,

Ratio by weight, sand/cement=3.0,

Ratio by weight, water/cement=0.6.

2) Slump Value:

Measured according to JIS A-1173.

(This is an index indicating the dispersibility in cement mortar.)

3) Bending Strength:

Measured according to JIS A-6203.

4) Compression Strength:

Measured according to JIS A-6203.

-   -   100 parts of ion-exchanged water was added to 100 parts of the        additive for hydraulic substances, and well stirred by the use        of a stirrer. The physical properties of the resulting mixture        were measured in the manner mentioned below. The results are        given in Tables 1 and 2.

Water Resistance (Film Dissolution in Water):

At 20° C., the redispersed emulsion was formed into a film having athickness of 100 μm. The film was dipped in water at 20° C. for 24hours, and its dissolution was calculated according to the followingequation:

Dissolution (%)={1−(absolute dry weight of dipped film)/(absolute dryweight of non-dipped film))×100,

wherein the absolute dry weight of the non-dipped film is representedby:

wet weight of non-dipped film−(wet weight of non-dipped film×watercontent (%) of film/100);

the absolute dry weight of the dipped film means the weight of thedipped film absolutely dried at 105° C.

Property Evaluation of Joint Materials for Hydraulic Substances:Property of Joint Material for Cement Mortar:

The emulsion powders obtained in Examples 1 to 14 and ComparativeExamples 1 to 10 were directly used for joint materials, and the samplesthus constructed were tested in the manner mentioned below.

Adhesion Strength Test:

1) Substrate for Test

The concrete substrate for the test was formed of a standard formulationin the art of construction. Concretely, 300 parts of portland cement,800 parts of siliceous sand, 1000 parts of coarse aggregate (ballast)and 180 parts of water were kneaded and then cast into a plywood framehaving a size of 300 mm×300 mm×50 mm thickness. This was cured in alaboratory (temperature 20° C., relative humidity (RH) 65%) for 28 days.Thus constructed, the sheet was used as the substrate in this test.

2) Coating Mortar:

The coating mortar to be used in the test was prepared by kneadingcement, aggregate (standard sand) and water in accordance with themethod stipulated in 9.4 in JIS RS201. Concretely, the ratio by weightof cement to aggregate is 1/2, and the ratio of water to cement is socontrolled that the flow of the resulting mixture may be 170±5.

The cement used herein is normal portland cement stipulated in JIS RS210(portland cement); and the aggregate is Toyoura standard sand stipulatedin 9.2 in JIS RS210.

3) Method of Fabricating Test Samples:

The joint material was uniformly applied onto the surface of the testsubstrate of above 1), using a brush, and then left in an atmosphere at20° C. and 65% RH for 24 hours. The amount of the joint material appliedonto it was 50 g/m² in terms of the solid content thereof. Next, themortar of above 2) was applied onto it, using a metal trowel, to formthereon a mortar layer having a thickness of 6 mm, and then cured in anatmosphere at 20° C. and 80% RH for 48 hours. Further, this was cured ina laboratory for 26 days to be a test sample.

4) Test for Adhesion Strength in Standard Condition:

Through the mortar face thereof, the test sample fabricated in the above3) was cut into pieces each having a size of 40 mm×90 mm, to a depththat reaches the substrate. Thus cut, the test piece was tested for theadhesion strength, according to the test method stipulated in 5.6 in JISA6916. Five points in one sample were tested, and the data wereaveraged.

5) Test for Resistance to Heat Cycle (Durability Test):

The test samples fabricated in the above 3) were exposed to an IR lampfor 105 minutes so that its surface temperature could be 70° C., andthen sprinkled with water for 15 minutes. This is one heat cycle. Everysample was subjected to 300 heat cycles. In the test, the temperature ofwater applied to each sample was 15±5° C., and the amount of waterapplied to one sample was 6 liters/min. After 300 heat cycles, thesamples were left under ordinary condition for 24 hours, and then testedin the same manner as in the above 4).

6) Test for Resistance to Freezing and Thawing (Durability Test):

The test samples fabricated in the above 3) were dipped in water at20±3° C. for 15 hours, then dipped in a thermostat tank at −20±3° C. for3 hours, and thereafter dipped in a thermostat tank at 70±3° C. for 6hours. This is one freezing and thawing cycle. Every sample wassubjected to 50 cycles. After 50 cycles, the samples were left underordinary condition for 24 hours, and then tested in the same manner asin the above 4).

Emulsion Production Example 21

80 parts of aqueous 9.5% solution of ethylene-modified PVA (PVA-21having an ethylene unit content of 4 mol %, a degree of polymerizationof 1300, and a saponification degree of 93 mol %) was fed into apressure autoclave equipped with a nitrogen inlet mouth, a thermometerand a stirrer, heated up to 60° C., and then purged with nitrogen. 80parts of vinyl acetate was fed into it, and then ethylene was into it toan increased pressure of 4.9 MPa. 2 g of aqueous 0.5% hydrogen peroxidesolution and 0.3 g of aqueous 2% Rongalite solution were fed into itunder pressure, and the polymerization was then started. When theremaining vinyl acetate concentration reached 10%, ethylene wasdischarged out until the ethylene pressure was lowered to 2.0 MPa. Then,0.3 g of aqueous 3% hydrogen peroxide solution was introduced into itunder pressure to complete the polymerization. During thepolymerization, no aggregation was found, and the polymerizationstability of the system was good. The process gave ethylene-vinylacetate copolymer emulsion (Em-21) having a solid concentration of 55%and an ethylene content of 18% by weight.

Emulsion Production Example 22

An ethylene-vinyl acetate copolymer emulsion (Em-22) having a solidconcentration of 55% and an ethylene content of 18.3% by weight wasproduced in the same manner as in Emulsion Production Example 21, forwhich, however, an ethylene-modified PVA (PVA-22 having an ethylene unitcontent of 3 mol %, a degree of polymerization of 500, and asaponification degree of 95 mol %) was used in place of PVA-21 inEmulsion Production Example 21.

Emulsion Production Example 23

An ethylene-vinyl acetate copolymer emulsion (Em-23) having a solidconcentration of 55% and an ethylene content of 17.8% by weight wasproduced in the same manner as in Emulsion Production Example 21, forwhich, however, an ethylene-modified PVA (PVA-23 having an ethylene unitcontent of 5 mol %, a degree of polymerization of 1300, and asaponification degree of 98 mol %) was used in place of PVA-21 inEmulsion Production Example 21.

Emulsion Production Example 24

An ethylene-vinyl acetate copolymer emulsion (Em-24) having a solidconcentration of 55% and an ethylene content of 18% by weight wasproduced in the same manner as in Emulsion Production Example 21, forwhich, however, a non-modified PVA (PVA-24 having a degree ofpolymerization of 1300, and a saponification degree of 93 mol %) wasused in place of PVA-21 in Emulsion Production Example 21.

Emulsion Production Example 25

An ethylene-vinyl acetate copolymer emulsion (Em-25) having a solidconcentration of 55% and an ethylene content of 18.4% by weight wasproduced in the same manner as in Emulsion Production Example 21, forwhich, however, a non-modified PVA (PVA-25 having a degree ofpolymerization of 500, and a saponification degree of 88 mol %,Kuraray's “PVA205”) was used in place of PVA-21 in Emulsion ProductionExample 21.

Emulsion Production Example 26

An ethylene-vinyl acetate copolymer emulsion (Em-26) having a solidconcentration of 55% and an ethylene content of 18.1% by weight wasproduced in the same manner as in Emulsion Production Example 21, forwhich, however, a non-modified PVA (PVA-26 having a degree ofpolymerization of 1000, and a saponification degree of 98.5 mol %,Kuraray's “PVA110”) was used in place of PVA-21 in Emulsion ProductionExample 21.

Emulsion Production Example 27

An ethylene-vinyl acetate copolymer emulsion (Em-27) having a solidconcentration of 55% and an ethylene content of 17.8% by weight wasproduced in the same manner as in Emulsion Production Example 21, forwhich, however, an ethylene-modified PVA (PVA-27 having an ethylene unitcontent of 3 mol %, a 1,2-glycol bond content of 1.9 mol %, a degree ofpolymerization of 1300, and a saponification degree of 93 mol %) thathad been prepared through high-temperature polymerization was used inplace of PVA-21 in Emulsion Production Example 21.

Emulsion Production Example 28

An ethylene-vinyl acetate copolymer emulsion (Em-28) having a solidconcentration of 55% and an ethylene content of 17.9% by weight wasproduced in the same manner as in Emulsion Production Example 21, forwhich, however, an ethylene-modified PVA (PVA-28 having an ethylene unitcontent of 5 mol %, al, 2-glycol bond content of 2.2 mol %, a degree ofpolymerization of 500, and a saponification degree of 93 mol %) that hadbeen prepared through high-temperature polymerization was used in placeof PVA-21 in Emulsion Production Example 21.

Emulsion Production Example 29

An ethylene-vinyl acetate copolymer emulsion (Em-29) having a solidconcentration of 55% and an ethylene content of 17.8% by weight wasproduced in the same manner as in Emulsion Production Example 21, forwhich, however, an ethylene-modified PVA (PVA-29 having an ethylene unitcontent of 2.5 mol %, a 1,2-glycol bond content of 1.6 mol %, a degreeof polymerization of 500, and a saponification degree of 88 mol %) wasused in place of PVA-21 in Emulsion Production Example 21.

Emulsion Production Example 210

An ethylene-vinyl acetate copolymer emulsion (Em-210) having a solidconcentration of 55% and an ethylene content of 17.8% by weight wasproduced in the same manner as in Emulsion Production Example 21, forwhich, however, an ethylene-modified PVA (PVA-210 having an ethyleneunit content of 1.5 mol %, a 1,2-glycol bond content of 1.6 mol %, adegree of polymerization of 500, and a saponification degree of 88 mol%) was used in place of PVA-21 in Emulsion Production Example 21.

Emulsion Production Example 211

An ethylene-vinyl acetate copolymer emulsion (Em-211) having a solidconcentration of 55% and an ethylene content of 17.8% by weight wasproduced in the same manner as in Emulsion Production Example 21, forwhich, however, an ethylene-modified PVA (PVA-211 having an ethyleneunit content of 0.5 mol %, a 1,2-glycol bond content of 1.6 mol %, adegree of polymerization of 500, and a saponification degree of 95 mol%) was used in place of PVA-21 in Emulsion Production Example 21.

Emulsion Production Example 212

Emulsion polymerization was tried in the same manner as in EmulsionProduction Example 21, using an ethylene-modified PVA (PVA-212 having anethylene unit content of 25 mol %, a 1,2-glycol bond content of 1.1 mol%, a degree of polymerization of 500, and a saponification degree of 95mol %) in place of PVA-21 in Emulsion Production Example 21. In this,however, the system was unstable during emulsion polymerization, and itcould not produce an emulsion.

Emulsion Production Example 213

5 parts of ethylene-modified PVA (PVA-21) and 90 parts of ion-exchangedwater were fed into a glass vessel equipped with a reflux condenser, adropping funnel, a thermometer, a nitrogen inlet mouth and a stirrer,and completely dissolved at 95° C. Next, its pH was made to be 4 withdiluted sulfuric acid added thereto, and then 10 parts of methylmethacrylate, 10 parts of n-butyl acrylate and 0.1 parts ofn-dodecylmercaptan were added to it with stirring at 150 rpm. This waspurged with nitrogen and heated up to 70° C. 5 parts of 1% potassiumpersulfate was added to it to start the polymerization. Then, a mixtureof 40 parts of methyl methacrylate, 40 parts of n-butyl acrylate and 0.4parts of n-dodecylmercaptan was continuously added to it, over a periodof 2 hours. 3 hours after the start of the polymerization, theconversion reached 99.2%, and the polymerization was stopped in thisstage. The process gave stable methyl methacrylate/n-butyl acrylatecopolymer emulsion (Em-212) having a solid concentration of 51.5%.

Emulsion Production Example 214

A methyl methacrylate/n-butyl acrylate copolymer emulsion (Em-213)having a solid concentration of 52% was produced in the same manner asin Emulsion Production Example 213, for which, however, non-modified PVA(PVA-25) was used in place of PVA-21 in Emulsion Production Example 213.

Emulsion Production Example 215

5 parts of mercapto-terminated PVA (having an ethylene content of 0.5mol %, a degree of polymerization of 550, a saponification degree of88.3 mol % and a mercapto group content of 3.3×10⁻⁵ equivalent/g)(PVA-213) and 90 parts of ion-exchanged water were fed into a glassvessel equipped with a reflux condenser, a dropping funnel, athermometer, a nitrogen inlet mouth and a stirrer, and completelydissolved at 95° C. Next, its pH was made to be 4 with diluted sulfuricacid added thereto, and then 10 parts of methyl methacrylate, 10 partsof n-butyl acrylate and 0.1 parts of n-dodecylmercaptan were added to itwith stirring at 150 rpm. This was purged with nitrogen and heated up to70° C. 5 parts of 1% potassium persulfate was added to it to start thepolymerization. Then, a mixture of 40 parts of methyl methacrylate, 40parts of n-butyl acrylate and 0.4 parts of n-dodecylmercaptan wascontinuously added to it, over a period of 2 hours. 3 hours after thestart of the polymerization, the conversion reached 99.5%, and thepolymerization was stopped in this stage. The process gave stable methylmethacrylate/n-butyl acrylate copolymer emulsion (Em-214) having a solidconcentration of 52.0%.

Emulsion Production Example 216

An ethylene-vinyl acetate copolymer emulsion (Em-215) having a solidconcentration of 55% and an ethylene content of 17.8% by weight wasproduced in the same manner as in Emulsion Production Example 21, forwhich, however, PVA (having a 1,2-glycol bond content of 1.9 mol %, adegree of polymerization of 1300, and a saponification degree of 93 mol%) (PVA-214) that had been prepared through high-temperaturepolymerization was used in place of PVA-21 in Emulsion ProductionExample 21.

Example 21

100 parts of the ethylene-vinyl acetate copolymer emulsion (A) (Em-21)obtained in Emulsion Production Example 21 was diluted with 50 parts ofdistilled water added thereto, and 2%, relative to the solid content ofthe emulsion, of fine powder of silicic anhydride (having a meanparticle size of 2 μm) were separately sprayed into hot air at 120° C.at the same time and dried to obtain an emulsion powder having a meanparticle size of 20 μm.

Property Evaluation of Emulsion Powder:

The emulsion powder was evaluated in the same manner as in Example 1.

Property of Additive for Cement Mortar:

<1> Physical Test of Cement Mortar:

1) Mortar Composition:

Ratio by weight of solid content of aqueous emulsion/cement=0.10;

Ratio by weight of sand/cement=2.5;

Ratio by weight of water/cement=0.5.

2) Slump Value:

Measured according to JIS A-1173.

(This is an index indicating the dispersibility in cement mortar.)

3) Bending Strength:

Measured according to JIS A-6203.

4) Compression Strength:

Measured according to JIS A-6203.

Examples 22 to 27 Comparative Examples 21 to 24

Emulsion powders were produced in the same manner as in Example 21, forwhich, however, any of Em-22 to Em-211 prepared in Emulsion ProductionExamples 22 to 211 was used in place of Em-21 in Example 21. Also in thesame manner as in Example 21, the physical properties of the emulsionpowders thus obtained herein were measured and evaluated. The resultsare given in Table 2-1.

Examples 28 to 210

A mixture of 100 parts of the ethylene-vinyl acetate copolymer emulsion(A) (Em-21) that had been prepared in Emulsion Production Example 21 anda predetermined amount of aqueous 5% solution of ethylene-modified PVA(B) (PVA-22), and 2%, relative to the solid content of the emulsion, offine powder of silicic anhydride were separately sprayed into hot air at120° C. at the same time and dried to obtain an emulsion powder. Theresults are given in Table 2-1.

Example 211 Comparative Examples 25 to 27

Emulsion powders were produced in the same manner as in Example 21, forwhich, however, any of methyl methacrylate/n-butyl acrylate copolymeremulsions (A) (Em-212, Em-213, Em-214, Em-215) prepared in EmulsionProduction Examples 213 to 216 was used in place of Em-21 in Example 21.Also in the same manner as in Example 21, the physical properties of theemulsion powders thus obtained herein were measured and evaluated. Theresults are given in Table 2-1.

Example 212

A mixture of 100 parts of the methyl acrylate/n-butyl acrylate copolymeremulsion (A) (Em-212) that had been prepared in Emulsion ProductionExample 213 and 200 parts of aqueous 5% solution of ethylene-modifiedPVA (B) (PVA-22), and 2%, relative to the solid content of the emulsion,of fine powder of silicic anhydride were separately sprayed into hot airat 120° C. at the same time and dried to obtain an emulsion powder. Theresults are given in Table 2-1.

PVA Production Example 31

2940 g of vinyl acetate, 60 g of methanol and 0.088 g of tartaric acidwere fed into a 5-liter pressure reactor equipped with a stirrer, anitrogen inlet mouth and an initiator inlet mouth, and, while this wasbubbled with nitrogen gas at room temperature, the pressure in thereactor was increased up to 2.0 MPa, left as such for 10 minutes, andthen degassed. This operation was repeated three times whereby thereactor was thus purged with nitrogen. An initiator,2,2′-azobis(cyclohexane-1-carbonitrile) (V-40) was dissolved in methanolto prepare an initiator solution having a concentration of 0.2 g/liter,which was then bubbled and purged with nitrogen gas. Next, thepolymerization reactor was heated to have an inner temperature of 120°C., and the pressure in the reactor in this stage was 0.5 MPa. Next, 2.5ml of the initiator solution was introduced into the reactor to startthe polymerization. During the polymerization, the temperature of thesystem was kept at 120° C., and the initiator solution of V-40 wascontinuously added to the system at a rate of 10.0 ml/hr. During thepolymerization in that condition, the pressure in the reactor was 0.5MPa. After 3 hours, this was cooled to terminate the polymerization. Inthis stage, the solid concentration in the resulting reaction system was24%. Next, methanol was intermittently added to the system at 30° C.under reduced pressure to remove the residual vinyl acetate monomer. Theprocess thus gave a methanol solution of polyvinyl acetate(concentration, 33%). Methanol was added to the thus-obtained polyvinylacetate solution to make it have a polymer concentration of 25%. 400 gof the thus-controlled methanol solution of polyvinyl acetate (100 g ofpolyvinyl acetate in the solution) was subjected to saponification at40° C. with an alkali solution (methanol solution of 10% NaOH) addedthereto. The amount of the alkali solution added to the polymer solutionwas 7 g, and this corresponds to a molar ratio (MR) of alkali to thevinyl acetate unit in the polyvinyl acetate, of 0.015. About 2 minutesafter the alkali addition, the system gelled and this was ground in amill and then left as such for 1 hour to promote the saponification ofthe polymer. Next, 1000 g of methyl acetate was added to it toneutralize the remaining alkali. With a phenolphthalein indicator, thetermination of the neutralization was confirmed. Then, a white solid PVAwas collected through filtration. 1000 g of methanol was added to thethus-collected PVA and kept at room temperature for 3 hours, with whichthe polymer PVA was thus washed. The washing operation was repeatedthree times. Then, this was dewatered through centrifugation, and theresulting PVA was dried in a drier at 70° C. for 2 days to obtain a dryPVA (PVA-31). Thus obtained, the PVA (PVA-31) had a saponificationdegree of 88 mol %. On the other hand, the methanol solution ofpolyvinyl acetate that had been obtained by removing the residual vinylacetate monomer after the polymerization was subject to saponificationwith an alkali at an alkali molar ratio of 0.5, then ground and kept at60° C. for 5 hours to promote the saponification of the polymer. Then,this was subjected to Soxhlet extraction washing with methanol for 3days and then dried at 80° C. under reduced pressure for 3 days toobtain a purified PVA. The mean degree of polymerization of the PVA wasmeasured in an ordinary manner of JIS K6726, and was 1700. The1,2-glycol bond content of PVA can be obtained from the peak appearingin the NMR pattern thereof. Concretely, PVA to be analyzed is subjectedto saponification to have a saponification degree of at least 99.9 mol%, then well washed with methanol, and dried at 90° C. under reducedpressure for 2 days. Thus processed, the PVA is dissolved in DMSO-D6 anda few drops of trifluoroacetic acid are added thereto to prepare asample. This is subjected to 500 MHz-proton NMR (JEOL GX-500) at 80° C.to obtain its NMR pattern.

The peak derived from the methine group in the vinyl alcohol unit in PVAis assigned to 3.2 to 4.0 ppm (integral value A), and the peak derivedfrom one methine group of the 1,2-glycol bond therein is assigned to3.25 ppm (integral value B), and the 1,2-glycol bond content of PVA iscalculated according to the following formula:

1,2-Glycol bond content (mol %)=B/A×100.

The 1,2-glycol bond content of the pure PVA produced herein was obtainedfrom the data in 500 MHz-proton NMR (with JEOL GX-500) in the samemanner as described above, and it was 2.2 mol %.

PVA Production Example 32

2400 g of vinyl acetate, 600 g of methanol and 0.088 g of tartaric acidwere fed into a 5-liter pressure reactor equipped with a stirrer, anitrogen inlet mouth and an initiator inlet mouth, and, while this wasbubbled with nitrogen gas at room temperature, the pressure in thereactor was increased up to 2.0 MPa, left as such for 10 minutes, andthen degassed. This operation was repeated three times whereby thereactor was thus purged with nitrogen. An initiator,2,2′-azobis(cyclohexane-1-carbonitrile) (V-40) was dissolved in methanolto prepare an initiator solution having a concentration of 0.2 g/liter,which was then bubbled and purged with nitrogen gas. Next, thepolymerization reactor was heated to have an inner temperature of 120°C., and the pressure in the reactor in this stage was 0.5 MPa. Next, 2.5ml of the initiator solution was introduced into the reactor to startthe polymerization. During the polymerization, the temperature of thesystem was kept at 120° C., and the initiator solution of V-40 wascontinuously added to the system at a rate of 10.0 ml/hr. During thepolymerization in that condition, the pressure in the reactor was 0.5MPa. After 3 hours, this was cooled to terminate the polymerization. Inthis stage, the solid concentration in the resulting reaction system was24%. Next, methanol was intermittently added to the system at 30° C.under reduced pressure to remove the residual vinyl acetate monomer. Theprocess thus gave a methanol solution of polyvinyl acetate(concentration, 33%). Methanol was added to the thus-obtained polyvinylacetate solution to make it have a polymer concentration of 25%. 400 gof the thus-controlled methanol solution of polyvinyl acetate (100 g ofpolyvinyl acetate in the solution) was subjected to saponification at40° C. with an alkali solution (methanol solution of 10% NaOH) addedthereto. The amount of the alkali solution added to the polymer solutionwas 7 g, and this corresponds to a molar ratio (MR) of alkali to thevinyl acetate unit in the polyvinyl acetate, of 0.015. About 2 minutesafter the alkali addition, the system gelled and this was ground in amill and then left as such for 1 hour to promote the saponification ofthe polymer. Next, 1000 g of methyl acetate was added to it toneutralize the remaining alkali. With a phenolphthalein indicator, thetermination of the neutralization was confirmed. Then, a white solid PVAwas collected through filtration. 1000 g of methanol was added to thethus-collected PVA and kept at room temperature for 3 hours, with whichthe polymer PVA was thus washed. The washing operation was repeatedthree times. Then, this was dewatered through centrifugation, and theresulting PVA was dried in a drier at 70° C. for 2 days to obtain a dryPVA (PVA-32). Thus obtained, the PVA (PVA-32) had a saponificationdegree of 98 mol %. On the other hand, the methanol solution ofpolyvinyl acetate that had been obtained by removing the residual vinylacetate monomer after the polymerization was subject to saponificationwith an alkali at an alkali molar ratio of 0.5, then ground and kept at60° C. for 5 hours to promote the saponification of the polymer. Then,this was subjected to Soxhlet extraction washing with methanol for 3days and then dried at 80° C. under reduced pressure for 3 days toobtain a purified PVA. The mean degree of polymerization of the PVA wasmeasured in an ordinary manner of JIS K6726, and was 500. The 1,2-glycolbond content of the pure PVA was obtained through 500 MHz-proton NMR(with JEOL GX-500) in the same manner as above, and it was 2.2 mol %.

PVA Production Example 33

2850 g of vinyl acetate, 150 g of methanol and 0.086 g of tartaric acidwere fed into a 5-liter pressure reactor equipped with a stirrer, anitrogen inlet mouth and an initiator inlet mouth, and, while this wasbubbled with nitrogen gas at room temperature, the pressure in thereactor was increased up to 2.0 MPa, left as such for 10 minutes, andthen degassed. This operation was repeated three times whereby thereactor was thus purged with nitrogen. An initiator,2,2′-azobis(N-butyl-2-methylpropionamide) was dissolved in methanol toprepare an initiator solution having a concentration of 0.1 g/liter,which was then bubbled and purged with nitrogen gas. Next, thepolymerization reactor was heated to have an inner temperature of 150°C., and the pressure in the reactor in this stage was 1.0 MPa. Next,15.0 ml of the initiator solution was introduced into the reactor tostart the polymerization. During the polymerization, the temperature ofthe system was kept at 150° C., and the initiator solution of2,2′-azobis(N-butyl-2-methylpropionamide) was continuously added to thesystem at a rate of 15.8 ml/hr. During the polymerization in thatcondition, the pressure in the reactor was 1.0 MPa. After 4 hours, thiswas cooled to terminate the polymerization. In this stage, the solidconcentration in the resulting reaction system was 35%. Next, methanolwas intermittently added to the system at 30° C. under reduced pressureto remove the residual vinyl acetate monomer. The process thus gave amethanol solution of polyvinyl acetate (concentration, 33%). Methanolwas added to the thus-obtained polyvinylacetate solution to make it havea polymer concentration of 25%. 400 g of the thus-controlled methanolsolution of polyvinyl acetate (100 g of polyvinyl acetate in thesolution) was subject to saponification at 40° C. with an alkalisolution (methanol solution of 10% NaOH) added thereto. The amount ofthe alkali solution added to the polymer solution was 11.6 g, and thiscorresponds to a molar ratio (MR) of alkali to the vinyl acetate unit inthe polyvinylacetate, of 0.025. About 3 minutes after the alkaliaddition, the system gelled and this was ground in a mill and then leftas such for 1 hour to promote the saponification of the polymer. Next,1000 g of methyl acetate was added to it to neutralize the remainingalkali. With a phenolphthalein indicator, the termination of theneutralization was confirmed. Then, a white solid PVA was collectedthrough filtration. 1000 g of methanol was added to the thus-collectedPVA and kept at room temperature for 3 hours, with which the polymer PVAwas thus washed. The washing operation was repeated three times. Then,this was dewatered through centrifugation, and the resulting PVA wasdried in a drier at 70° C. for 2 days to obtain a dry PVA (PVA-33). Thusobtained, the PVA (PVA-33) had a saponification degree of 98 mol %. Onthe other hand, the methanol solution of polyvinyl acetate that had beenobtained by removing the non-reacted vinyl acetate monomer after thepolymerization was subjected to saponification with an alkali at analkali molar ratio of 0.5, then ground and kept at 60° C. for 5 hours topromote the saponification of the polymer. Then, this was subjected toSoxhlet extraction washing with methanol for 3 days and then dried at80° C. under reduced pressure for 3 days to obtain a purified PVA. Themean degree of polymerization of the PVA was measured in an ordinarymanner of JIS K6726, and was 1000. The 1,2-glycol bond content of thepure PVA was obtained through 500 MHz-proton NMR (with JEOL GX-500) inthe same manner as above, and it was 2.5 mol %.

PVA Production Example 34

2700 g of vinyl acetate, 300 g of methanol and 0.081 g of tartaric acidwere fed into a 5-liter pressure reactor equipped with a stirrer, anitrogen inlet mouth and an initiator inlet mouth, and, while this wasbubbled with nitrogen gas at room temperature, the pressure in thereactor was increased up to 2.0 MPa, left as such for 10 minutes, andthen degassed. This operation was repeated three times whereby thereactor was thus purged with nitrogen. An initiator,2,2′-azobis(N-butyl-2-methylpropionamide) was dissolved in methanol toprepare an initiator solution having a concentration of 0.05 g/liter,which was then bubbled and purged with nitrogen gas. Next, thepolymerization reactor was heated to have an inner temperature of 180°C., and the pressure in the reactor in this stage was 1.6 MPa. Next, 0.4ml of the initiator solution was introduced into the reactor to startthe polymerization. During the polymerization, the temperature of thesystem was kept at 180° C., and the initiator solution of2,2′-azobis(N-butyl-2-methylpropionamide) was continuously added to thesystem at a rate of 10.6 ml/hr. During the polymerization in thatcondition, the pressure in the reactor was 1.6 MPa. After 4 hours, thiswas cooled to terminate the polymerization. In this stage, the solidconcentration in the resulting reaction system was 27%. Next, methanolwas intermittently added to the system at 30° C. under reduced pressureto remove the residual vinyl acetate monomer. The process thus gave amethanol solution of polyvinyl acetate (concentration, 33%). Methanolwas added to the thus-obtained polyvinylacetate solution to make it havea polymer concentration of 30%. 333 g of the thus-controlled methanolsolution of polyvinyl acetate (100 g of polyvinyl acetate in thesolution) was subjected to saponification at 40° C. with an alkalisolution (methanol solution of 10% NaOH) added thereto. The amount ofthe alkali solution added to the polymer solution was 11.6 g, and thiscorresponds to a molar ratio (MR) of alkali to the vinyl acetate unit inthe polyvinylacetate, of 0.025. About 3 minutes after the alkaliaddition, the system gelled and this was ground in a mill and then leftas such for 1 hour to promote the saponification of the polymer. Next,1000 g of methyl acetate was added to it to neutralize the remainingalkali. With a phenolphthalein indicator, the termination of theneutralization was confirmed. Then, a white solid PVA was collectedthrough filtration. 1000 g of methanol was added to the thus-collectedPVA and kept at room temperature for 3 hours, with which the polymer PVAwas thus washed. The washing operation was repeated three times. Then,this was dewatered through centrifugation, and the resulting PVA wasdried in a drier at 70° C. for 2 days to obtain a dry PVA (PVA-34). Thusobtained, the PVA (PVA-34) had a saponification degree of 98 mol %. Onthe other hand, the methanol solution of polyvinyl acetate that had beenobtained by removing the non-reacted vinyl acetate monomer after thepolymerization was subjected to saponification with an alkali at analkali molar ratio of 0.5, then ground and kept at 60° C. for 5 hours topromote the saponification of the polymer. Then, this was subjected toSoxhlet extraction washing with methanol for 3 days and then dried at80° C. under reduced pressure for 3 days to obtain a purified PVA. Themean degree of polymerization of the PVA was measured in an ordinarymanner of JIS K6726, and was 500. The 1,2-glycol bond content of thepure PVA was obtained through 500 MHz-proton NMR (with JEOL GX-500) inthe same manner as above, and it was 2.9 mol %.

PVA Production Example 35

2850 g of vinyl acetate, 150 g of methanol and 0.086 g of tartaric acidwere fed into a 5-liter pressure reactor equipped with a stirrer, anitrogen inlet mouth and an initiator inlet mouth, and, while this wasbubbled with nitrogen gas at room temperature, the pressure in thereactor was increased up to 2.0 MPa, left as such for 10 minutes, andthen degassed. This operation was repeated three times whereby thereactor was thus purged with nitrogen. An initiator,2,2′-azobis(N-butyl-2-methylpropionamide) was dissolved in methanol toprepare an initiator solution having a concentration of 0.1 g/liter,which was then bubbled and purged with nitrogen gas. Next, thepolymerization reactor was heated to have an inner temperature of 150°C., and the pressure in the reactor in this stage was 1.0 MPa. Next,15.0 ml of the initiator solution was introduced into the reactor tostart the polymerization. During the polymerization, the temperature ofthe system was kept at 150° C., and the initiator solution of2,2′-azobis(N-butyl-2-methylpropionamide) was continuously added to thesystem at a rate of 15.8 ml/hr. During the polymerization in thatcondition, the pressure in the reactor was 1.0 MPa. After 4 hours, thiswas cooled to terminate the polymerization. In this stage, the solidconcentration in the resulting reaction system was 35%. Next, methanolwas intermittently added to the system at 30° C. under reduced pressureto remove the residual vinyl acetate monomer. The process thus gave amethanol solution of polyvinyl acetate (concentration, 33%). Methanolwas added to the thus-obtained polyvinyl acetate solution to make ithave a polymer concentration of 25%. 400 g of the thus-controlledmethanol solution of polyvinyl acetate (100 g of polyvinyl acetate inthe solution) was subjected to saponification at 40° C. with an alkalisolution (methanol solution of 10% NaOH) added thereto. The amount ofthe alkali solution added to the polymer solution was 7 g, and thiscorresponds to a molar ratio (MR) of alkali to the vinyl acetate unit inthe polyvinyl acetate, of 0.015. About 3 minutes after the alkaliaddition, the system gelled and this was ground in a mill and then leftas such for 1 hour to promote the saponification of the polymer. Next,1000 g of methyl acetate was added to it to neutralize the remainingalkali. With a phenolphthalein indicator, the termination of theneutralization was confirmed. Then, a white solid PVA was collectedthrough filtration. 1000 g of methanol was added to the thus-collectedPVA and kept at room temperature for 3 hours, with which the polymer PVAwas thus washed. The washing operation was repeated three times. Then,this was dewatered through centrifugation, and the resulting PVA wasdried in a drier at 70° C. for 2 days to obtain a dry PVA (PVA-35). Thusobtained, the PVA (PVA-35) had a saponification degree of 88 mol %. Onthe other hand, the methanol solution of polyvinyl acetate that had beenobtained by removing the non-reacted vinyl acetate monomer after thepolymerization was subjected saponification with an alkali at an alkalimolar ratio of 0.5, then ground and kept at 60° C. for 5 hours topromote the saponification of the polymer. Then, this was subjected toSoxhlet extraction washing with methanol for 3 days and then dried at80° C. under reduced pressure for 3 days to obtain a purified PVA. Themean degree of polymerization of the PVA was measured in an ordinarymanner of JIS K6726, and was 1000. The 1,2-glycol bond content of thepure PVA was obtained through 500 MHz-proton NMR (with JEOL GX-500) inthe same manner as above, and it was 2.5 mol %.

Emulsion Production Example 31

80 parts of aqueous 9.5% solution of “PVA217” (by Kuraray, having adegree of polymerization of 1700 and a saponification degree of 88 mol%) was fed into a pressure autoclave equipped with a nitrogen inletmouth, a thermometer and a stirrer, heated up to 60° C., and then purgedwith nitrogen. 80 parts of vinyl acetate was fed into it, and thenethylene was into it to an increased pressure of 4.9 MPa. 2 g of aqueous0.5% hydrogen peroxide solution and 0.3 g of aqueous 2% Rongalitesolution were fed into it under pressure, and the polymerization wasthen started. When the remaining vinyl acetate concentration reached10%, ethylene was discharged out until the ethylene pressure was loweredto 2.0 MPa. Then, 0.3 g of aqueous 3% hydrogen peroxide solution wasintroduced into it under pressure to complete the polymerization. Duringthe polymerization, no aggregation was found, and the polymerizationstability of the system was good. The process gave ethylene-vinylacetate copolymer emulsion (Em-31) having a solid concentration of 55%and an ethylene content of 18% by weight.

Emulsion Production Example 32

5 parts of mercapto-terminated PVA (having a degree of polymerization of550, a saponification degree of 88.3 mol % and a mercapto group contentof 3.3×10⁻⁵ equivalent/g) and 90 parts of ion-exchanged water were fedinto a glass vessel equipped with a reflux condenser, a dropping funnel,a thermometer, a nitrogen inlet mouth and a stirrer, and completelydissolved at 95° C. Next, its pH was made to be 4 with diluted sulfuricacid added thereto, and then 10 parts of methyl methacrylate, 10 partsof n-butyl acrylate and 0.1 parts of n-dodecylmercaptan were added to itwith stirring at 150 rpm. This was purged with nitrogen and heated up to70° C. 5 parts of 1% potassium persulfate was added to it to start thepolymerization. Then, a mixture of 40 parts of methyl methacrylate, 40parts of n-butyl acrylate and 0.4 parts of n-dodecylmercaptan wascontinuously added to it, over a period of 2 hours. 3 hours after thestart of the polymerization, the conversion reached 99.5%, and thepolymerization was stopped in this stage. The process gave stable methylmethacrylate/n-butyl acrylate copolymer emulsion (Em-32) having a solidconcentration of 52.0%.

Emulsion Production Example 33

An emulsion (Em-33) was produced in the same manner as in EmulsionProduction Example 31, for which, however, PVA-31 that had been producedin PVA Production Example 31 was used in place of “PVA217” in EmulsionProduction Example 31.

Example 31

A mixture of 100 parts, in terms of the solid content thereof, of theethylene-vinyl acetate copolymer emulsion (A) (Em-31) obtained inEmulsion Production Example 31 and 200 parts of aqueous 5% solution ofPVA-32 obtained in PVA Production Example 32, and 2%, relative to thesolid content of the emulsion, of fine powder of silicic anhydride(having a mean particle size of 2 μm) were separately sprayed into hotair at 120° C. at the same time and dried to obtain an emulsion powderhaving a mean particle size of 20 μm. The physical properties of theemulsion powder are given in Table 3-1.

Property Evaluation of Emulsion Powder:

The emulsion powder was evaluated in the same manner as in Example 1.

Property Evaluation of Additives for Hydraulic Substances:

Property of Additives for Cement Mortar

Evaluated in the same manner as in Example 1. The results are given inTable 3-2.

Property Evaluation of Joint Materials for Hydraulic Substances:

Property of Joint Material for Cement Mortar:

The additives for hydraulic substances obtained in the above wasdirectly used for joint materials for hydraulic substances, and thesamples thus constructed were tested and evaluated in the same manner asin Example 1. The data of the property for joint material are given inTable 3-2.

Comparative Example 31

An emulsion powder was produced in the same manner as in Example 31, forwhich, however, ordinary PVA (PVA-36 having a degree of polymerizationof 500, a saponification degree of 98.5 mol %, and a 1,2-glycol bondcontent of 1.6 mol %—Kuraray's “PVA105”) was used in place of PVA-32 inExample 31. Its data are given in Table 3-1 and Table 3-2.

Example 32

An emulsion powder was produced in the same manner as in Example 31, forwhich, however, PVA-33 that had been obtained in PVA Production Example33 was used in place of PVA-32 in Example 31. Its data are given inTable 3-1 and Table 3-2.

Example 33

An emulsion powder was produced in the same manner as in Example 31, forwhich, however, PVA-34 that had been obtained in PVA Production Example34 was used in place of PVA-32 in Example 31. Its data are given inTable 3-1 and Table 3-2.

Example 34

An emulsion powder was produced in the same manner as in Example 31, forwhich, however, PVA-35 that had been obtained in PVA Production Example35 was used in place of PVA-32 in Example 31. Its data are given inTable 3-1 and Table 3-2.

Comparative Example 32

An emulsion powder was produced in the same manner as in Example 31, forwhich, however, ordinary PVA (PVA-37 having a degree of polymerizationof 1000, a saponification degree of 88 mol %, and a 1,2-glycol bondcontent of 1.6 mol %—Kuraray's “PVA210”) was used in place of PVA-32 inExample 31. Its data are given in Table 3-1 and Table 3-2.

Comparative Example 33

An emulsion powder was produced in the same manner as in Example 31, forwhich, however, PVA-32 was not used. This was tested and evaluated inthe same manner as in Example 31. However, since its redispersibilitywas extremely bad and its film formability was bad, the emulsion powercould not be tested and evaluated for the film dissolution and thestability thereof. The results are given in Table 3-1 and Table 3-2.

Example 35

An emulsion powder was produced in the same manner as in Example 31, forwhich, however, 100 parts but not 200 parts of the aqueous 5% solutionof PVA-32 was used. Its data are given in Table 3-1 and Table 3-2.

Comparative Example 34

An emulsion powder was produced in the same manner as in ComparativeExample 31, for which, however, 100 parts but not 200 parts of theaqueous 5% solution of PVA-36 was used. However, since itsredispersibility was extremely bad and its film formability was bad, theemulsion power could not be tested and evaluated for the filmdissolution and the stability thereof. The results are given in Table3-1 and Table 3-2.

Example 36

An emulsion powder was produced in the same manner as in Example 31, forwhich, however, 300 parts but not 200 parts of the aqueous 5% solutionof PVA-32 was used. Its data are given in Table 3-1 and Table 3-2.

Example 37

An emulsion powder was produced in the same manner as in Example 31, forwhich, however, 40 parts but not 200 parts of the aqueous 5% solution ofPVA-32 was used. Its data are given in Table 3-1 and Table 3-2.

Example 38

An emulsion powder was produced in the same manner as in Example 31, forwhich, however, 500 parts but not 200 parts of the aqueous 5% solutionof PVA-32 was used. Its data are given in Table 3-1 and Table 3-2.

Example 39

An emulsion powder was produced in the same manner as in Example 31, forwhich, however, the methyl methacrylate/n-butyl acrylate copolymeremulsion (A) (Em-32) that had been prepared in Emulsion ProductionExample 32 was used in place of Em-31 in Example 31. Its data are givenin Table 3-1 and Table 3-2.

Comparative Example 35

An emulsion powder was produced in the same manner as in Example 39, forwhich, however, ordinary PVA (PVA-36) was used in place of PVA-32 inExample 39. Its data are given in Table 3-1 and Table 3-2.

Example 310

An emulsion powder was produced in the same manner as in Example 31, forwhich, however, Em-33 was used in place of Em-31 in Example 31. Its dataare given in Table 3-1 and Table 3-2.

Comparative Example 36

An emulsion powder was produced in the same manner as in Example 31, forwhich, however, Em-33 was used in place of Em-31 and PVA (B) (PVA-32)was not used. Its data are given in Table 3-1 and Table 3-2.

Comparative Example 37

An emulsion powder was produced in the same manner as in Example 310,for which, however, PVA (B) (PVA-36 having a degree of polymerization of500, a saponification degree of 98.5 mol % and a 1,2-glycol bond contentof 1.6 mol %—Kuraray's “PVA105”) was used in place of PVA (B) (PVA-32)in Example 310. Its data are given in Table 3-1 and Table 3-2.

As described in detail hereinabove with reference to its preferredembodiments, the invention provides synthetic resin emulsion powder ofgood redispersibility and water resistance. The redispersion of theresin emulsion powder of the invention well forms good films, and itsstorage stability at low temperatures is good.

Using the emulsion powder of the invention realizes good additives tohydraulic substances, which well disperse in hydraulic substances suchas cement mortar and which give hardened hydraulic substances of highmechanical strength. In addition, using the emulsion powder of theinvention also realizes joint materials for hydraulic substances, whichhave good adhesiveness and durability and which give jointed hydraulicsubstances of high mechanical strength.

TABLE 1 PVA (B) ethylene 1,2-glycol Saponification Emulsion modificationcontent Degree of degree amount (A) (mol %) (mol %) polymerization (mol%) (part) Example 1 Em-1 PVA-1 5 1.5 500 95 10 Example 2 Em-1 PVA-2 101.5 500 98 10 Example 3 Em-1 PVA-3 5 1.5 500 88 10 Comp. Ex. 1 Em-1PVA-4 0 1.6 500 98.5 10 Comp. Ex. 2 Em-1 PVA-5 0 1.6 500 88 10 Comp. Ex.3 Em-1 no — — — — 0 Example 4 Em-1 PVA-6 5 1.5 1300 93 10 Comp. Ex. 4Em-1 PVA-7 0 1.6 1300 95 10 Example 5 Em-1 PVA-1 5 1.5 500 95 5 Example6 Em-1 PVA-1 5 1.5 500 95 15 Example 7 Em-1 PVA-1 5 1.5 500 95 2 Example8 Em-1 PVA-1 5 1.5 500 95 25 Example 9 Em-1 PVA-8 2.5 1.6 500 88 10Example 10 Em-1 PVA-9 1.5 1.6 500 88 10 Comp. Ex. 5 Em-1 PVA-10 0.5 1.6500 95 10 Comp. Ex. 6 Em-1 PVA-11 25 1.1 500 95 10 Example 11 Em-1PVA-12 3 1.9 1300 93 10 Example 12 Em-1 PVA-13 5 2.2 500 88 10 Example13 Em-2 PVA-1 5 1.5 500 95 10 Comp. Ex. 7 Em-2 PVA-5 0 1.6 500 88 10Comp. Ex. 8 Em-3 PVA-4 0 1.6 500 98.5 10 Comp. Ex. 9 Em-1 PVA-14 15 1.31300 93 10 Comp. Ex. 10 Em-1 PVA-15 propylene 5 1.5 1300 98 10 Example14 Em-4 PVA-1 5 1.5 500 95 10 Redispersibility Film Storage fillerresidue Film Dissolution Gel Content Stability (%) condition Formability(%) (%) 0° C. 20° C. Example 1 0.5 ⊚ ◯ 2.7 25 ◯ ◯ Example 2 3 ◯ ◯ 1.1 22◯ ◯ Example 3 0.3 ⊚ ◯ 3.7 35 ◯ ◯ Comp. Ex. 1 35 Δ Δ 7.8 12 X ◯ Comp. Ex.2 5 ◯ ◯ 15 28 ◯ ◯ Comp. Ex. 3 80 X X — — — — Example 4 2 ◯ ◯ 1.8 30 ◯ ◯Comp. Ex. 4 40 Δ Δ 9 17 Δ ◯ Example 5 1 ⊚ ◯ 0.6 27 ◯ ◯ Example 6 0.8 ⊚ ◯4.1 21 ◯ ◯ Example 7 4.3 ◯ ◯ 1.3 28 ◯ ◯ Example 8 3 ◯ ◯ 6.3 20 ◯ ◯Example 9 0.7 ⊚ ◯ 3.8 30 ◯ ◯ Example 10 3.4 ◯ ◯ 6.7 25 ◯ ◯ Comp. Ex. 54.7 ◯ ◯ 8.2 17 Δ ◯ Comp. Ex. 6 50 X X — — X X Example 11 0.8 ⊚ ◯ 1.3 35◯ ◯ Example 12 0.1 ⊚ ◯ 3.5 40 ◯ ◯ Example 13 1.4 ⊚ ◯ 2.5 24 ◯ ◯ Comp.Ex. 7 6 ◯ ◯ 18 27 ◯ ◯ Comp. Ex. 8 5.7 ◯ ◯ 7.3 11 Δ ◯ Comp. Ex. 9 52 X X— — X X Comp. Ex. 10 13 Δ Δ 14 15 ◯ ◯ Example 14 0.3 ⊚ ◯ 2.4 43 ◯ ◯

TABLE 2 Physical Properties of Joint Material Physical Properties ofMortar Adhesion Strength slump bending strength compression strengthstandard condition after heat cycle after frozen and thawed (mm)(kg/cm²) (kg/cm²) (kg/cm²) (kg/cm²) (kg/cm²) Example 1 34 76 177 20 1513 Example 2 28 70 169 19 15 13 Example 3 38 80 179 20 15 13 Comp. Ex. 115 50 145 13 10 7 Comp. Ex. 2 20 55 150 15 11 7 Comp. Ex. 3 10 40 120 —— — Example 4 31 71 173 18 14 12 Comp. Ex. 4 14 54 143 13 10 7 Example 533 74 176 20 15 12 Example 6 35 77 179 20 15 13 Example 7 27 70 168 1813 11 Example 8 28 71 169 19 14 11 Example 9 33 75 174 21 16 14 Example10 28 69 165 19 15 13 Comp. Ex. 5 25 65 160 16 11 8 Comp. Ex. 6 — — — —— — Example 11 35 78 179 20 14 12 Example 12 38 80 181 21 16 14 Example13 37 75 174 19 15 13 Comp. Ex. 7 22 56 157 15 10 7 Comp. Ex. 8 32 60161 14  9 6 Comp. Ex. 9 — — — — — — Comp. Ex. 10 18 53 146 12 10 7Example 14 40 82 185 22 18 15

TABLE 2-1 Emulsion (A) ethylene 1,2-glycol Saponification PVA (B)modification content degree of degree amount PVA (mol %) (mol %)polymerization (mol %) (part) Example 21 Em-21 PVA-21 4 1.5 1300 93 — —Example 22 Em-22 PVA-22 3 1.5 500 95 — — Example 23 Em-23 PVA-23 5 1.51300 98 — — Comp. Ex. 21 Em-24 PVA-24 0 1.6 1300 93 — — Comp. Ex. 22Em-25 PVA-25 0 1.6 500 88 — — Comp. Ex. 23 Em-26 PVA-26 0 1.6 1000 98.5— — Example 24 Em-27 PVA-27 3 1.9 1300 93 — — Example 25 Em-28 PVA-28 52.2 500 93 — — Example 26 Em-29 PVA-29 2.5 1.6 500 88 — — Example 27Em-210 PVA-210 1.5 1.6 500 88 — — Comp. Ex. 24 Em-211 PVA-211 0.5 1.6500 95 — — Example 28 Em-21 PVA-21 4 1.5 1300 93 PVA- 10 22 Example 29Em-21 PVA-21 4 1.5 1300 93 PVA- 2 22 Example 210 Em-21 PVA-21 4 1.5 130093 PVA- 25 22 Example 211 Em-212 PVA-21 4 1.5 1300 93 — — Comp. Ex. 25Em-213 PVA-25 0 1.6 500 88 — — Example 212 Em-212 PVA-21 4 1.5 1300 93PVA- 10 22 Comp. Ex. 26 Em-214 PVA-213 0.5 1.6 550 88.3 — — Comp. Ex. 27Em-215 PVA-214 0 1.9 1300 93 — — Redispersibility Physical Properties ofMortar filter film Gel bending compression residue film dissolutioncontent slump strength strength (%) condition formability (%) (%) (mm)(kg/cm²) (kg/cm²) Example 21 1.1 ◯ ◯ 4.5 55 35 75 179 Example 22 0.8 ⊚ ◯4 50 38 82 181 Example 23 2.8 ◯ ◯ 3.8 45 33 70 175 Comp. Ex. 21 30 Δ Δ 725 20 55 160 Comp. Ex. 22 8 ◯ ◯ 15 33 26 60 165 Comp. Ex. 23 76 X X — —— — — Example 24 0.6 ⊚ ◯ 4.4 55 37 80 182 Example 25 0.6 ⊚ ◯ 3.9 52 3682 180 Example 26 1.3 ⊚ ◯ 6 54 36 78 177 Example 27 2.9 ◯ ◯ 8 45 33 70170 Comp. Ex. 24 5.1 Δ ◯ 12 35 24 57 158 Example 28 0.5 ⊚ ◯ 6.7 46 36 80225 Example 29 2.7 ◯ ◯ 5.3 51 30 70 218 Example 210 2.5 ◯ ◯ 7.8 40 31 72220 Example 211 0.8 ⊚ ◯ 4.7 53 35 79 180 Comp. Ex. 25 10 Δ ◯ 16 35 28 67166 Example 212 0.6 ⊚ ◯ 6.4 44 36 80 233 Comp. Ex. 26 6 ◯ ◯ 14 30 29 61160 Comp. Ex. 27 5.5 ◯ ◯ 13 24 28 60 163

TABLE 3-1 PVA (B) saponi- Film 1,2-glycol degree ficationRedispersibility Disso- Gel Storage content of polym- degree amountfilter Film lution Content Stability Emulsion (A) (mol %) erization (mol%) C part residue condition Formability (%) (%) 0° C. Example 31 Em-31PVA-32 2.2 500 98 10 0.1 ⊚ ◯ 4.7 25 ◯ Comp. Ex. 31 Em-31 PVA-36 1.6 50098.5 10 35 Δ Δ 7.8 12 X Example 32 Em-31 PVA-33 2.5 1000 98 10 0.2 ⊚ ◯4.4 27 ◯ Example 33 Em-31 PVA-34 2.9 500 98 10 0.1 ⊚ ◯ 4.9 28 ◯ Example34 Em-31 PVA-35 2.5 1000 88 10 0.1 ⊚ ◯ 5.3 38 ◯ Comp. Ex. 32 Em-31PVA-37 1.6 1000 88 10 6 ◯ ◯ 12 28 ◯ Comp. Ex. 33 Em-31 no — — — 0 80 X X— — — Example 35 Em-31 PVA-32 2.2 500 98 5 0.2 ⊚ ◯ 2.4 29 ◯ Comp. Ex. 34Em-31 PVA-36 1.6 500 98.5 5 60 X X — — — Example 36 Em-31 PVA-32 2.2 50098 15 0.1 ⊚ ◯ 6.2 22 ◯ Example 37 Em-31 PVA-32 2.2 500 98 2 0.5 ◯ ◯ 1.331 ◯ Example 38 Em-31 PVA-32 2.2 500 98 25 0.1 ⊚ ◯ 6.5 20 ◯ Example 39Em-32 PVA-32 2.2 500 98 10 0.2 ⊚ ◯ 4.2 25 ◯ Comp. Ex. 35 Em-32 PVA-361.6 500 98.5 10 30 Δ Δ 7.4 11 ◯ Example 310 Em-33 PVA-32 2.2 500 98 100.1 ⊚ ◯ 3.5 26 ◯ Comp. Ex. 36 Em-33 no — — — 0 1.3 ◯ ◯ 2.5 18 ◯ Comp.Ex. 37 Em-33 PVA-36 1.6 500 98.5 5 4.5 Δ Δ 7.5 17 X

TABLE 3-2 Physical Properties of Physical Properties of Mortar JointMaterial bending standard Slump strength compression condition (mm)(kg/cm²) strength (kg/cm²) (kg/cm²) Example 31 36 77 180 21 Comp. Ex. 3115 50 145 13 Example 32 33 73 170 19 Example 33 37 78 182 23 Example 3435 75 175 20 Comp. Ex. 32 29 65 161 15 Comp. Ex. 33 — — — — Example 3534 75 175 19 Comp. Ex. 34 — — — — Example 36 38 77 182 22 Example 37 3169 167 17 Example 38 37 70 172 19 Example 39 36 76 178 20 Comp. Ex. 3514 45 140 12 Example 310 38 79 183 23 Comp. Ex. 36 30 68 165 17 Comp.Ex. 37 15 48 143 12

1-12. (canceled)
 13. A synthetic resin emulsion powder, obtained by: (i)forming a polymer emulsion (A) comprising a dispersant and a dispersoid,(ii) mixing the polymer emulsion (A) with a polyvinyl alcohol (C) toform an emulsion composition, (iii) drying the emulsion composition,wherein the dispersoid is a polymer having one or more unsaturatedmonomer units selected from the group consisting of ethylenicunsaturated monomers and dienic monomers, and wherein the polyvinylalcohol (C) has an ethylene unit content of from 1 to 12 mol %.
 14. Thesynthetic resin emulsion powder as claimed in claim 13, wherein thepolyvinyl alcohol (C) is not chemically bonded with the dispersoid. 15.The synthetic resin emulsion powder as claimed in claim 13, wherein theethylene unit content of the dispersant is from 2 to 12 mol %.
 16. Thesynthetic resin emulsion powder as claimed in claim 13, wherein theethylene unit content of the dispersant is from 5 to 10 mol %.
 17. Thesynthetic resin emulsion powder as claimed in claim 13, wherein theethylene unit content of the dispersant is from 1.5 to 5 mol %.
 18. Thesynthetic resin emulsion powder as claimed in claim 13, wherein thepolyvinyl alcohol (C) is a polyvinyl alcohol having a 1,2-glycol bondcontent of at least 1.9 mol %.
 19. The synthetic resin emulsion powderas claimed in claim 13, comprising from 1 to 50 parts by weight of thepolyvinyl alcohol (C) relative to 100 parts by weight of the dispersoid.20. The synthetic resin emulsion powder as claimed in claim 13, furthercomprising an inorganic powder.
 21. The synthetic resin emulsion powderas claimed in claim 13 for which the drying is spray-drying.
 22. Anadditive or joint material for hydraulic substances, comprising thesynthetic resin powder of claim 13.